linux/kernel/time/tick-sched.c

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/*
* linux/kernel/time/tick-sched.c
*
* Copyright(C) 2005-2006, Thomas Gleixner <tglx@linutronix.de>
* Copyright(C) 2005-2007, Red Hat, Inc., Ingo Molnar
* Copyright(C) 2006-2007 Timesys Corp., Thomas Gleixner
*
* No idle tick implementation for low and high resolution timers
*
* Started by: Thomas Gleixner and Ingo Molnar
*
* Distribute under GPLv2.
*/
#include <linux/cpu.h>
#include <linux/err.h>
#include <linux/hrtimer.h>
#include <linux/interrupt.h>
#include <linux/kernel_stat.h>
#include <linux/percpu.h>
#include <linux/profile.h>
#include <linux/sched.h>
#include <linux/module.h>
#include <asm/irq_regs.h>
#include "tick-internal.h"
/*
* Per cpu nohz control structure
*/
static DEFINE_PER_CPU(struct tick_sched, tick_cpu_sched);
/*
* The time, when the last jiffy update happened. Protected by xtime_lock.
*/
static ktime_t last_jiffies_update;
[PATCH] Add debugging feature /proc/timer_list add /proc/timer_list, which prints all currently pending (high-res) timers, all clock-event sources and their parameters in a human-readable form. Sample output: Timer List Version: v0.1 HRTIMER_MAX_CLOCK_BASES: 2 now at 4246046273872 nsecs cpu: 0 clock 0: .index: 0 .resolution: 1 nsecs .get_time: ktime_get_real .offset: 1273998312645738432 nsecs active timers: clock 1: .index: 1 .resolution: 1 nsecs .get_time: ktime_get .offset: 0 nsecs active timers: #0: <f5a90ec8>, hrtimer_sched_tick, hrtimer_stop_sched_tick, swapper/0 # expires at 4246432689566 nsecs [in 386415694 nsecs] #1: <f5a90ec8>, hrtimer_wakeup, do_nanosleep, pcscd/2050 # expires at 4247018194689 nsecs [in 971920817 nsecs] #2: <f5a90ec8>, hrtimer_wakeup, do_nanosleep, irqbalance/1909 # expires at 4247351358392 nsecs [in 1305084520 nsecs] #3: <f5a90ec8>, hrtimer_wakeup, do_nanosleep, crond/2157 # expires at 4249097614968 nsecs [in 3051341096 nsecs] #4: <f5a90ec8>, it_real_fn, do_setitimer, syslogd/1888 # expires at 4251329900926 nsecs [in 5283627054 nsecs] .expires_next : 4246432689566 nsecs .hres_active : 1 .check_clocks : 0 .nr_events : 31306 .idle_tick : 4246020791890 nsecs .tick_stopped : 1 .idle_jiffies : 986504 .idle_calls : 40700 .idle_sleeps : 36014 .idle_entrytime : 4246019418883 nsecs .idle_sleeptime : 4178181972709 nsecs cpu: 1 clock 0: .index: 0 .resolution: 1 nsecs .get_time: ktime_get_real .offset: 1273998312645738432 nsecs active timers: clock 1: .index: 1 .resolution: 1 nsecs .get_time: ktime_get .offset: 0 nsecs active timers: #0: <f5a90ec8>, hrtimer_sched_tick, hrtimer_restart_sched_tick, swapper/0 # expires at 4246050084568 nsecs [in 3810696 nsecs] #1: <f5a90ec8>, hrtimer_wakeup, do_nanosleep, atd/2227 # expires at 4261010635003 nsecs [in 14964361131 nsecs] #2: <f5a90ec8>, hrtimer_wakeup, do_nanosleep, smartd/2332 # expires at 5469485798970 nsecs [in 1223439525098 nsecs] .expires_next : 4246050084568 nsecs .hres_active : 1 .check_clocks : 0 .nr_events : 24043 .idle_tick : 4246046084568 nsecs .tick_stopped : 0 .idle_jiffies : 986510 .idle_calls : 26360 .idle_sleeps : 22551 .idle_entrytime : 4246043874339 nsecs .idle_sleeptime : 4170763761184 nsecs tick_broadcast_mask: 00000003 event_broadcast_mask: 00000001 CPU#0's local event device: Clock Event Device: lapic capabilities: 0000000e max_delta_ns: 807385544 min_delta_ns: 1443 mult: 44624025 shift: 32 set_next_event: lapic_next_event set_mode: lapic_timer_setup event_handler: hrtimer_interrupt .installed: 1 .expires: 4246432689566 nsecs CPU#1's local event device: Clock Event Device: lapic capabilities: 0000000e max_delta_ns: 807385544 min_delta_ns: 1443 mult: 44624025 shift: 32 set_next_event: lapic_next_event set_mode: lapic_timer_setup event_handler: hrtimer_interrupt .installed: 1 .expires: 4246050084568 nsecs Clock Event Device: hpet capabilities: 00000007 max_delta_ns: 2147483647 min_delta_ns: 3352 mult: 61496110 shift: 32 set_next_event: hpet_next_event set_mode: hpet_set_mode event_handler: handle_nextevt_broadcast Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: john stultz <johnstul@us.ibm.com> Cc: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-16 09:28:15 +00:00
struct tick_sched *tick_get_tick_sched(int cpu)
{
return &per_cpu(tick_cpu_sched, cpu);
}
/*
* Must be called with interrupts disabled !
*/
static void tick_do_update_jiffies64(ktime_t now)
{
unsigned long ticks = 0;
ktime_t delta;
/*
* Do a quick check without holding xtime_lock:
*/
delta = ktime_sub(now, last_jiffies_update);
if (delta.tv64 < tick_period.tv64)
return;
/* Reevalute with xtime_lock held */
write_seqlock(&xtime_lock);
delta = ktime_sub(now, last_jiffies_update);
if (delta.tv64 >= tick_period.tv64) {
delta = ktime_sub(delta, tick_period);
last_jiffies_update = ktime_add(last_jiffies_update,
tick_period);
/* Slow path for long timeouts */
if (unlikely(delta.tv64 >= tick_period.tv64)) {
s64 incr = ktime_to_ns(tick_period);
ticks = ktime_divns(delta, incr);
last_jiffies_update = ktime_add_ns(last_jiffies_update,
incr * ticks);
}
do_timer(++ticks);
/* Keep the tick_next_period variable up to date */
tick_next_period = ktime_add(last_jiffies_update, tick_period);
}
write_sequnlock(&xtime_lock);
}
/*
* Initialize and return retrieve the jiffies update.
*/
static ktime_t tick_init_jiffy_update(void)
{
ktime_t period;
write_seqlock(&xtime_lock);
/* Did we start the jiffies update yet ? */
if (last_jiffies_update.tv64 == 0)
last_jiffies_update = tick_next_period;
period = last_jiffies_update;
write_sequnlock(&xtime_lock);
return period;
}
/*
* NOHZ - aka dynamic tick functionality
*/
#ifdef CONFIG_NO_HZ
/*
* NO HZ enabled ?
*/
static int tick_nohz_enabled __read_mostly = 1;
/*
* Enable / Disable tickless mode
*/
static int __init setup_tick_nohz(char *str)
{
if (!strcmp(str, "off"))
tick_nohz_enabled = 0;
else if (!strcmp(str, "on"))
tick_nohz_enabled = 1;
else
return 0;
return 1;
}
__setup("nohz=", setup_tick_nohz);
/**
* tick_nohz_update_jiffies - update jiffies when idle was interrupted
*
* Called from interrupt entry when the CPU was idle
*
* In case the sched_tick was stopped on this CPU, we have to check if jiffies
* must be updated. Otherwise an interrupt handler could use a stale jiffy
* value. We do this unconditionally on any cpu, as we don't know whether the
* cpu, which has the update task assigned is in a long sleep.
*/
static void tick_nohz_update_jiffies(ktime_t now)
{
int cpu = smp_processor_id();
struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
unsigned long flags;
ts->idle_waketime = now;
local_irq_save(flags);
tick_do_update_jiffies64(now);
local_irq_restore(flags);
touch_softlockup_watchdog();
}
/*
* Updates the per cpu time idle statistics counters
*/
static void
update_ts_time_stats(int cpu, struct tick_sched *ts, ktime_t now, u64 *last_update_time)
{
ktime_t delta;
if (ts->idle_active) {
delta = ktime_sub(now, ts->idle_entrytime);
if (nr_iowait_cpu(cpu) > 0)
ts->iowait_sleeptime = ktime_add(ts->iowait_sleeptime, delta);
else
ts->idle_sleeptime = ktime_add(ts->idle_sleeptime, delta);
ts->idle_entrytime = now;
}
if (last_update_time)
*last_update_time = ktime_to_us(now);
}
static void tick_nohz_stop_idle(int cpu, ktime_t now)
{
struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
update_ts_time_stats(cpu, ts, now, NULL);
ts->idle_active = 0;
sched_clock_idle_wakeup_event(0);
}
static ktime_t tick_nohz_start_idle(int cpu, struct tick_sched *ts)
{
ktime_t now = ktime_get();
ts->idle_entrytime = now;
ts->idle_active = 1;
sched_clock_idle_sleep_event();
return now;
}
/**
* get_cpu_idle_time_us - get the total idle time of a cpu
* @cpu: CPU number to query
* @last_update_time: variable to store update time in. Do not update
* counters if NULL.
*
* Return the cummulative idle time (since boot) for a given
* CPU, in microseconds.
*
* This time is measured via accounting rather than sampling,
* and is as accurate as ktime_get() is.
*
* This function returns -1 if NOHZ is not enabled.
*/
u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time)
{
struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
ktime_t now, idle;
if (!tick_nohz_enabled)
return -1;
now = ktime_get();
if (last_update_time) {
update_ts_time_stats(cpu, ts, now, last_update_time);
idle = ts->idle_sleeptime;
} else {
if (ts->idle_active && !nr_iowait_cpu(cpu)) {
ktime_t delta = ktime_sub(now, ts->idle_entrytime);
idle = ktime_add(ts->idle_sleeptime, delta);
} else {
idle = ts->idle_sleeptime;
}
}
return ktime_to_us(idle);
}
EXPORT_SYMBOL_GPL(get_cpu_idle_time_us);
/**
* get_cpu_iowait_time_us - get the total iowait time of a cpu
* @cpu: CPU number to query
* @last_update_time: variable to store update time in. Do not update
* counters if NULL.
*
* Return the cummulative iowait time (since boot) for a given
* CPU, in microseconds.
*
* This time is measured via accounting rather than sampling,
* and is as accurate as ktime_get() is.
*
* This function returns -1 if NOHZ is not enabled.
*/
u64 get_cpu_iowait_time_us(int cpu, u64 *last_update_time)
{
struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
ktime_t now, iowait;
if (!tick_nohz_enabled)
return -1;
now = ktime_get();
if (last_update_time) {
update_ts_time_stats(cpu, ts, now, last_update_time);
iowait = ts->iowait_sleeptime;
} else {
if (ts->idle_active && nr_iowait_cpu(cpu) > 0) {
ktime_t delta = ktime_sub(now, ts->idle_entrytime);
iowait = ktime_add(ts->iowait_sleeptime, delta);
} else {
iowait = ts->iowait_sleeptime;
}
}
return ktime_to_us(iowait);
}
EXPORT_SYMBOL_GPL(get_cpu_iowait_time_us);
static void tick_nohz_stop_sched_tick(struct tick_sched *ts, ktime_t now)
{
nohz: Separate out irq exit and idle loop dyntick logic The tick_nohz_stop_sched_tick() function, which tries to delay the next timer tick as long as possible, can be called from two places: - From the idle loop to start the dytick idle mode - From interrupt exit if we have interrupted the dyntick idle mode, so that we reprogram the next tick event in case the irq changed some internal state that requires this action. There are only few minor differences between both that are handled by that function, driven by the ts->inidle cpu variable and the inidle parameter. The whole guarantees that we only update the dyntick mode on irq exit if we actually interrupted the dyntick idle mode, and that we enter in RCU extended quiescent state from idle loop entry only. Split this function into: - tick_nohz_idle_enter(), which sets ts->inidle to 1, enters dynticks idle mode unconditionally if it can, and enters into RCU extended quiescent state. - tick_nohz_irq_exit() which only updates the dynticks idle mode when ts->inidle is set (ie: if tick_nohz_idle_enter() has been called). To maintain symmetry, tick_nohz_restart_sched_tick() has been renamed into tick_nohz_idle_exit(). This simplifies the code and micro-optimize the irq exit path (no need for local_irq_save there). This also prepares for the split between dynticks and rcu extended quiescent state logics. We'll need this split to further fix illegal uses of RCU in extended quiescent states in the idle loop. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Mike Frysinger <vapier@gentoo.org> Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Cc: David Miller <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Paul Mackerras <paulus@samba.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-10-07 16:22:06 +00:00
unsigned long seq, last_jiffies, next_jiffies, delta_jiffies;
ktime_t last_update, expires;
cpuidle: consolidate 2.6.22 cpuidle branch into one patch commit e5a16b1f9eec0af7cfa0830304b41c1c0833cf9f Author: Len Brown <len.brown@intel.com> Date: Tue Oct 2 23:44:44 2007 -0400 cpuidle: shrink diff processor_idle.c | 440 +++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 429 insertions(+), 11 deletions(-) Signed-off-by: Len Brown <len.brown@intel.com> commit dfbb9d5aedfb18848a3e0d6f6e3e4969febb209c Author: Len Brown <len.brown@intel.com> Date: Wed Sep 26 02:17:55 2007 -0400 cpuidle: reduce diff size Reduces the cpuidle processor_idle.c diff vs 2.6.22 from this processor_idle.c | 2006 ++++++++++++++++++++++++++----------------- 1 file changed, 1219 insertions(+), 787 deletions(-) to this: processor_idle.c | 502 +++++++++++++++++++++++++++++++++++++++---- 1 file changed, 458 insertions(+), 44 deletions(-) ...for the purpose of making the cpuilde patch less invasive and easier to review. no functional changes. build tested only. Signed-off-by: Len Brown <len.brown@intel.com> commit 889172fc915f5a7fe20f35b133cbd205ce69bf6c Author: Venki Pallipadi <venkatesh.pallipadi@intel.com> Date: Thu Sep 13 13:40:05 2007 -0700 cpuidle: Retain old ACPI policy for !CONFIG_CPU_IDLE Retain the old policy in processor_idle, so that when CPU_IDLE is not configured, old C-state policy will still be used. This provides a clean gradual migration path from old ACPI policy to new cpuidle based policy. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> commit 9544a8181edc7ecc33b3bfd69271571f98ed08bc Author: Venki Pallipadi <venkatesh.pallipadi@intel.com> Date: Thu Sep 13 13:39:17 2007 -0700 cpuidle: Configure governors by default Quoting Len "Do not give an option to users to shoot themselves in the foot". Remove the configurability of ladder and menu governors as they are needed for default policy of cpuidle. That way users will not be able to have cpuidle without any policy loosing all C-state power savings. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> commit 8975059a2c1e56cfe83d1bcf031bcf4cb39be743 Author: Adam Belay <abelay@novell.com> Date: Tue Aug 21 18:27:07 2007 -0400 CPUIDLE: load ACPI properly when CPUIDLE is disabled Change the registration return codes for when CPUIDLE support is not compiled into the kernel. As a result, the ACPI processor driver will load properly even if CPUIDLE is unavailable. However, it may be possible to cleanup the ACPI processor driver further and eliminate some dead code paths. Signed-off-by: Adam Belay <abelay@novell.com> Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> commit e0322e2b58dd1b12ec669bf84693efe0dc2414a8 Author: Adam Belay <abelay@novell.com> Date: Tue Aug 21 18:26:06 2007 -0400 CPUIDLE: remove cpuidle_get_bm_activity() Remove cpuidle_get_bm_activity() and updates governors accordingly. Signed-off-by: Adam Belay <abelay@novell.com> Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> commit 18a6e770d5c82ba26653e53d240caa617e09e9ab Author: Adam Belay <abelay@novell.com> Date: Tue Aug 21 18:25:58 2007 -0400 CPUIDLE: max_cstate fix Currently max_cstate is limited to 0, resulting in no idle processor power management on ACPI platforms. This patch restores the value to the array size. Signed-off-by: Adam Belay <abelay@novell.com> Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> commit 1fdc0887286179b40ce24bcdbde663172e205ef0 Author: Adam Belay <abelay@novell.com> Date: Tue Aug 21 18:25:40 2007 -0400 CPUIDLE: handle BM detection inside the ACPI Processor driver Update the ACPI processor driver to detect BM activity and limit state entry depth internally, rather than exposing such requirements to CPUIDLE. As a result, CPUIDLE can drop this ACPI-specific interface and become more platform independent. BM activity is now handled much more aggressively than it was in the original implementation, so some testing coverage may be needed to verify that this doesn't introduce any DMA buffer under-run issues. Signed-off-by: Adam Belay <abelay@novell.com> Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> commit 0ef38840db666f48e3cdd2b769da676c57228dd9 Author: Adam Belay <abelay@novell.com> Date: Tue Aug 21 18:25:14 2007 -0400 CPUIDLE: menu governor updates Tweak the menu governor to more effectively handle non-timer break events. Non-timer break events are detected by comparing the actual sleep time to the expected sleep time. In future revisions, it may be more reliable to use the timer data structures directly. Signed-off-by: Adam Belay <abelay@novell.com> Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> commit bb4d74fca63fa96cf3ace644b15ae0f12b7df5a1 Author: Adam Belay <abelay@novell.com> Date: Tue Aug 21 18:24:40 2007 -0400 CPUIDLE: fix 'current_governor' sysfs entry Allow the "current_governor" sysfs entry to properly handle input terminated with '\n'. Signed-off-by: Adam Belay <abelay@novell.com> Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> commit df3c71559bb69b125f1a48971bf0d17f78bbdf47 Author: Len Brown <len.brown@intel.com> Date: Sun Aug 12 02:00:45 2007 -0400 cpuidle: fix IA64 build (again) Signed-off-by: Len Brown <len.brown@intel.com> commit a02064579e3f9530fd31baae16b1fc46b5a7bca8 Author: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Date: Sun Aug 12 01:39:27 2007 -0400 cpuidle: Remove support for runtime changing of max_cstate Remove support for runtime changeability of max_cstate. Drivers can use use latency APIs. max_cstate can still be used as a boot time option and dmi override. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> commit 0912a44b13adf22f5e3f607d263aed23b4910d7e Author: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Date: Sun Aug 12 01:39:16 2007 -0400 cpuidle: Remove ACPI cstate_limit calls from ipw2100 ipw2100 already has code to use accetable_latency interfaces to limit the C-state. Remove the calls to acpi_set_cstate_limit and acpi_get_cstate_limit as they are redundant. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> commit c649a76e76be6bff1fd770d0a775798813a3f6e0 Author: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Date: Sun Aug 12 01:35:39 2007 -0400 cpuidle: compile fix for pause and resume functions Fix the compilation failure when cpuidle is not compiled in. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Acked-by: Adam Belay <adam.belay@novell.com> Signed-off-by: Len Brown <len.brown@intel.com> commit 2305a5920fb8ee6ccec1c62ade05aa8351091d71 Author: Adam Belay <abelay@novell.com> Date: Thu Jul 19 00:49:00 2007 -0400 cpuidle: re-write Some portions have been rewritten to make the code cleaner and lighter weight. The following is a list of changes: 1.) the state name is now included in the sysfs interface 2.) detection, hotplug, and available state modifications are handled by CPUIDLE drivers directly 3.) the CPUIDLE idle handler is only ever installed when at least one cpuidle_device is enabled and ready 4.) the menu governor BM code no longer overflows 5.) the sysfs attributes are now printed as unsigned integers, avoiding negative values 6.) a variety of other small cleanups Also, Idle drivers are no longer swappable during runtime through the CPUIDLE sysfs inteface. On i386 and x86_64 most idle handlers (e.g. poll, mwait, halt, etc.) don't benefit from an infrastructure that supports multiple states, so I think using a more general case idle handler selection mechanism would be cleaner. Signed-off-by: Adam Belay <abelay@novell.com> Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Acked-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> commit df25b6b56955714e6e24b574d88d1fd11f0c3ee5 Author: Len Brown <len.brown@intel.com> Date: Tue Jul 24 17:08:21 2007 -0400 cpuidle: fix IA64 buid Signed-off-by: Len Brown <len.brown@intel.com> commit fd6ada4c14488755ff7068860078c437431fbccd Author: Adrian Bunk <bunk@stusta.de> Date: Mon Jul 9 11:33:13 2007 -0700 cpuidle: static make cpuidle_replace_governor() static Signed-off-by: Adrian Bunk <bunk@stusta.de> Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit c1d4a2cebcadf2429c0c72e1d29aa2a9684c32e0 Author: Adrian Bunk <bunk@stusta.de> Date: Tue Jul 3 00:54:40 2007 -0400 cpuidle: static This patch makes the needlessly global struct menu_governor static. Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit dbf8780c6e8d572c2c273da97ed1cca7608fd999 Author: Andrew Morton <akpm@linux-foundation.org> Date: Tue Jul 3 00:49:14 2007 -0400 export symbol tick_nohz_get_sleep_length ERROR: "tick_nohz_get_sleep_length" [drivers/cpuidle/governors/menu.ko] undefined! ERROR: "tick_nohz_get_idle_jiffies" [drivers/cpuidle/governors/menu.ko] undefined! And please be sure to get your changes to core kernel suitably reviewed. Cc: Adam Belay <abelay@novell.com> Cc: Venki Pallipadi <venkatesh.pallipadi@intel.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: john stultz <johnstul@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit 29f0e248e7017be15f99febf9143a2cef00b2961 Author: Andrew Morton <akpm@linux-foundation.org> Date: Tue Jul 3 00:43:04 2007 -0400 tick.h needs hrtimer.h It uses hrtimers. Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit e40cede7d63a029e92712a3fe02faee60cc38fb4 Author: Venki Pallipadi <venkatesh.pallipadi@intel.com> Date: Tue Jul 3 00:40:34 2007 -0400 cpuidle: first round of documentation updates Documentation changes based on Pavel's feedback. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit 83b42be2efece386976507555c29e7773a0dfcd1 Author: Venki Pallipadi <venkatesh.pallipadi@intel.com> Date: Tue Jul 3 00:39:25 2007 -0400 cpuidle: add rating to the governors and pick the one with highest rating by default Introduce a governor rating scheme to pick the right governor by default. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit d2a74b8c5e8f22def4709330d4bfc4a29209b71c Author: Venki Pallipadi <venkatesh.pallipadi@intel.com> Date: Tue Jul 3 00:38:08 2007 -0400 cpuidle: make cpuidle sysfs driver governor switch off by default Make default cpuidle sysfs to show current_governor and current_driver in read-only mode. More elaborate available_governors and available_drivers with writeable current_governor and current_driver interface only appear with "cpuidle_sysfs_switch" boot parameter. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit 1f60a0e80bf83cf6b55c8845bbe5596ed8f6307b Author: Venki Pallipadi <venkatesh.pallipadi@intel.com> Date: Tue Jul 3 00:37:00 2007 -0400 cpuidle: menu governor: change the early break condition Change the C-state early break out algorithm in menu governor. We only look at early breakouts that result in wakeups shorter than idle state's target_residency. If such a breakout is frequent enough, eliminate the particular idle state upto a timeout period. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit 45a42095cf64b003b4a69be3ce7f434f97d7af51 Author: Venki Pallipadi <venkatesh.pallipadi@intel.com> Date: Tue Jul 3 00:35:38 2007 -0400 cpuidle: fix uninitialized variable in sysfs routine Fix the uninitialized usage of ret. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit 80dca7cdba3e6ee13eae277660873ab9584eb3be Author: Venki Pallipadi <venkatesh.pallipadi@intel.com> Date: Tue Jul 3 00:34:16 2007 -0400 cpuidle: reenable /proc/acpi//power interface for the time being Keep /proc/acpi/processor/CPU*/power around for a while as powertop depends on it. It will be marked deprecated and removed in future. powertop can use cpuidle interfaces instead. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit 589c37c2646c5e3813a51255a5ee1159cb4c33fc Author: Venki Pallipadi <venkatesh.pallipadi@intel.com> Date: Tue Jul 3 00:32:37 2007 -0400 cpuidle: menu governor and hrtimer compile fix Compile fix for menu governor. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit 0ba80bd9ab3ed304cb4f19b722e4cc6740588b5e Author: Len Brown <len.brown@intel.com> Date: Thu May 31 22:51:43 2007 -0400 cpuidle: build fix - cpuidle vs ipw2100 module ERROR: "acpi_set_cstate_limit" [drivers/net/wireless/ipw2100.ko] undefined! Signed-off-by: Len Brown <len.brown@intel.com> commit d7d8fa7f96a7f7682be7c6cc0cc53fa7a18c3b58 Author: Adam Belay <abelay@novell.com> Date: Sat Mar 24 03:47:07 2007 -0400 cpuidle: add the 'menu' governor Here is my first take at implementing an idle PM governor that takes full advantage of NO_HZ. I call it the 'menu' governor because it considers the full list of idle states before each entry. I've kept the implementation fairly simple. It attempts to guess the next residency time and then chooses a state that would meet at least the break-even point between power savings and entry cost. To this end, it selects the deepest idle state that satisfies the following constraints: 1. If the idle time elapsed since bus master activity was detected is below a threshold (currently 20 ms), then limit the selection to C2-type or above. 2. Do not choose a state with a break-even residency that exceeds the expected time remaining until the next timer interrupt. 3. Do not choose a state with a break-even residency that exceeds the elapsed time between the last pair of break events, excluding timer interrupts. This governor has an advantage over "ladder" governor because it proactively checks how much time remains until the next timer interrupt using the tick infrastructure. Also, it handles device interrupt activity more intelligently by not including timer interrupts in break event calculations. Finally, it doesn't make policy decisions using the number of state entries, which can have variable residency times (NO_HZ makes these potentially very large), and instead only considers sleep time deltas. The menu governor can be selected during runtime using the cpuidle sysfs interface like so: "echo "menu" > /sys/devices/system/cpu/cpuidle/current_governor" Signed-off-by: Adam Belay <abelay@novell.com> Signed-off-by: Len Brown <len.brown@intel.com> commit a4bec7e65aa3b7488b879d971651cc99a6c410fe Author: Adam Belay <abelay@novell.com> Date: Sat Mar 24 03:47:03 2007 -0400 cpuidle: export time until next timer interrupt using NO_HZ Expose information about the time remaining until the next timer interrupt expires by utilizing the dynticks infrastructure. Also modify the main idle loop to allow dynticks to handle non-interrupt break events (e.g. DMA). Finally, expose sleep ticks information to external code. Thomas Gleixner is responsible for much of the code in this patch. However, I've made some additional changes, so I'm probably responsible if there are any bugs or oversights :) Signed-off-by: Adam Belay <abelay@novell.com> Signed-off-by: Len Brown <len.brown@intel.com> commit 2929d8996fbc77f41a5ff86bb67cdde3ca7d2d72 Author: Adam Belay <abelay@novell.com> Date: Sat Mar 24 03:46:58 2007 -0400 cpuidle: governor API changes This patch prepares cpuidle for the menu governor. It adds an optional stage after idle state entry to give the governor an opportunity to check why the state was exited. Also it makes sure the idle loop returns after each state entry, allowing the appropriate dynticks code to run. Signed-off-by: Adam Belay <abelay@novell.com> Signed-off-by: Len Brown <len.brown@intel.com> commit 3a7fd42f9825c3b03e364ca59baa751bb350775f Author: Venki Pallipadi <venkatesh.pallipadi@intel.com> Date: Thu Apr 26 00:03:59 2007 -0700 cpuidle: hang fix Prevent hang on x86-64, when ACPI processor driver is added as a module on a system that does not support C-states. x86-64 expects all idle handlers to enable interrupts before returning from idle handler. This is due to enter_idle(), exit_idle() races. Make cpuidle_idle_call() confirm to this when there is no pm_idle_old. Also, cpuidle look at the return values of attch_driver() and set current_driver to NULL if attach fails on all CPUs. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit 4893339a142afbd5b7c01ffadfd53d14746e858e Author: Shaohua Li <shaohua.li@intel.com> Date: Thu Apr 26 10:40:09 2007 +0800 cpuidle: add support for max_cstate limit With CPUIDLE framework, the max_cstate (to limit max cpu c-state) parameter is ingored. Some systems require it to ignore C2/C3 and some drivers like ipw require it too. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> commit 43bbbbe1cb998cbd2df656f55bb3bfe30f30e7d1 Author: Shaohua Li <shaohua.li@intel.com> Date: Thu Apr 26 10:40:13 2007 +0800 cpuidle: add cpuidle_fore_redetect_devices API add cpuidle_force_redetect_devices API, which forces all CPU redetect idle states. Next patch will use it. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> commit d1edadd608f24836def5ec483d2edccfb37b1d19 Author: Shaohua Li <shaohua.li@intel.com> Date: Thu Apr 26 10:40:01 2007 +0800 cpuidle: fix sysfs related issue Fix the cpuidle sysfs issue. a. make kobject dynamicaly allocated b. fixed sysfs init issue to avoid suspend/resume issue Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> commit 7169a5cc0d67b263978859672e86c13c23a5570d Author: Randy Dunlap <randy.dunlap@oracle.com> Date: Wed Mar 28 22:52:53 2007 -0400 cpuidle: 1-bit field must be unsigned A 1-bit bitfield has no room for a sign bit. drivers/cpuidle/governors/ladder.c:54:16: error: dubious bitfield without explicit `signed' or `unsigned' Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit 4658620158dc2fbd9e4bcb213c5b6fb5d05ba7d4 Author: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Date: Wed Mar 28 22:52:41 2007 -0400 cpuidle: fix boot hang Patch for cpuidle boot hang reported by Larry Finger here. http://www.ussg.iu.edu/hypermail/linux/kernel/0703.2/2025.html Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Cc: Larry Finger <larry.finger@lwfinger.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit c17e168aa6e5fe3851baaae8df2fbc1cf11443a9 Author: Len Brown <len.brown@intel.com> Date: Wed Mar 7 04:37:53 2007 -0500 cpuidle: ladder does not depend on ACPI build fix for CONFIG_ACPI=n In file included from drivers/cpuidle/governors/ladder.c:21: include/acpi/processor.h:88: error: expected specifier-qualifier-list before ‘acpi_integer’ include/acpi/processor.h:106: error: expected specifier-qualifier-list before ‘acpi_integer’ include/acpi/processor.h:168: error: expected specifier-qualifier-list before ‘acpi_handle’ Signed-off-by: Len Brown <len.brown@intel.com> commit 8c91d958246bde68db0c3f0c57b535962ce861cb Author: Adrian Bunk <bunk@stusta.de> Date: Tue Mar 6 02:29:40 2007 -0800 cpuidle: make code static This patch makes the following needlessly global code static: - driver.c: __cpuidle_find_driver() - governor.c: __cpuidle_find_governor() - ladder.c: struct ladder_governor Signed-off-by: Adrian Bunk <bunk@stusta.de> Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Cc: Adam Belay <abelay@novell.com> Cc: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit 0c39dc3187094c72c33ab65a64d2017b21f372d2 Author: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Date: Wed Mar 7 02:38:22 2007 -0500 cpu_idle: fix build break This patch fixes a build breakage with !CONFIG_HOTPLUG_CPU and CONFIG_CPU_IDLE. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit 8112e3b115659b07df340ef170515799c0105f82 Author: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Date: Tue Mar 6 02:29:39 2007 -0800 cpuidle: build fix for !CPU_IDLE Fix the compile issues when CPU_IDLE is not configured. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Cc: Adam Belay <abelay@novell.com> Cc: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit 1eb4431e9599cd25e0d9872f3c2c8986821839dd Author: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Date: Thu Feb 22 13:54:57 2007 -0800 cpuidle take2: Basic documentation for cpuidle Documentation for cpuidle infrastructure Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Adam Belay <abelay@novell.com> Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> commit ef5f15a8b79123a047285ec2e3899108661df779 Author: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Date: Thu Feb 22 13:54:03 2007 -0800 cpuidle take2: Hookup ACPI C-states driver with cpuidle Hookup ACPI C-states onto generic cpuidle infrastructure. drivers/acpi/procesor_idle.c is now a ACPI C-states driver that registers as a driver in cpuidle infrastructure and the policy part is removed from drivers/acpi/processor_idle.c. We use governor in cpuidle instead. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Adam Belay <abelay@novell.com> Signed-off-by: Len Brown <len.brown@intel.com> commit 987196fa82d4db52c407e8c9d5dec884ba602183 Author: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Date: Thu Feb 22 13:52:57 2007 -0800 cpuidle take2: Core cpuidle infrastructure Announcing 'cpuidle', a new CPU power management infrastructure to manage idle CPUs in a clean and efficient manner. cpuidle separates out the drivers that can provide support for multiple types of idle states and policy governors that decide on what idle state to use at run time. A cpuidle driver can support multiple idle states based on parameters like varying power consumption, wakeup latency, etc (ACPI C-states for example). A cpuidle governor can be usage model specific (laptop, server, laptop on battery etc). Main advantage of the infrastructure being, it allows independent development of drivers and governors and allows for better CPU power management. A huge thanks to Adam Belay and Shaohua Li who were part of this mini-project since its beginning and are greatly responsible for this patchset. This patch: Core cpuidle infrastructure. Introduces a new abstraction layer for cpuidle: * which manages drivers that can support multiple idles states. Drivers can be generic or particular to specific hardware/platform * allows pluging in multiple policy governors that can take idle state policy decision * The core also has a set of sysfs interfaces with which administrato can know about supported drivers and governors and switch them at run time. Signed-off-by: Adam Belay <abelay@novell.com> Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> Signed-off-by: Len Brown <len.brown@intel.com>
2007-10-03 22:58:00 +00:00
struct clock_event_device *dev = __get_cpu_var(tick_cpu_device).evtdev;
u64 time_delta;
int cpu;
cpu = smp_processor_id();
ts = &per_cpu(tick_cpu_sched, cpu);
/*
* If this cpu is offline and it is the one which updates
* jiffies, then give up the assignment and let it be taken by
* the cpu which runs the tick timer next. If we don't drop
* this here the jiffies might be stale and do_timer() never
* invoked.
*/
if (unlikely(!cpu_online(cpu))) {
if (cpu == tick_do_timer_cpu)
tick_do_timer_cpu = TICK_DO_TIMER_NONE;
}
if (unlikely(ts->nohz_mode == NOHZ_MODE_INACTIVE))
nohz: Separate out irq exit and idle loop dyntick logic The tick_nohz_stop_sched_tick() function, which tries to delay the next timer tick as long as possible, can be called from two places: - From the idle loop to start the dytick idle mode - From interrupt exit if we have interrupted the dyntick idle mode, so that we reprogram the next tick event in case the irq changed some internal state that requires this action. There are only few minor differences between both that are handled by that function, driven by the ts->inidle cpu variable and the inidle parameter. The whole guarantees that we only update the dyntick mode on irq exit if we actually interrupted the dyntick idle mode, and that we enter in RCU extended quiescent state from idle loop entry only. Split this function into: - tick_nohz_idle_enter(), which sets ts->inidle to 1, enters dynticks idle mode unconditionally if it can, and enters into RCU extended quiescent state. - tick_nohz_irq_exit() which only updates the dynticks idle mode when ts->inidle is set (ie: if tick_nohz_idle_enter() has been called). To maintain symmetry, tick_nohz_restart_sched_tick() has been renamed into tick_nohz_idle_exit(). This simplifies the code and micro-optimize the irq exit path (no need for local_irq_save there). This also prepares for the split between dynticks and rcu extended quiescent state logics. We'll need this split to further fix illegal uses of RCU in extended quiescent states in the idle loop. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Mike Frysinger <vapier@gentoo.org> Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Cc: David Miller <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Paul Mackerras <paulus@samba.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-10-07 16:22:06 +00:00
return;
if (need_resched())
nohz: Separate out irq exit and idle loop dyntick logic The tick_nohz_stop_sched_tick() function, which tries to delay the next timer tick as long as possible, can be called from two places: - From the idle loop to start the dytick idle mode - From interrupt exit if we have interrupted the dyntick idle mode, so that we reprogram the next tick event in case the irq changed some internal state that requires this action. There are only few minor differences between both that are handled by that function, driven by the ts->inidle cpu variable and the inidle parameter. The whole guarantees that we only update the dyntick mode on irq exit if we actually interrupted the dyntick idle mode, and that we enter in RCU extended quiescent state from idle loop entry only. Split this function into: - tick_nohz_idle_enter(), which sets ts->inidle to 1, enters dynticks idle mode unconditionally if it can, and enters into RCU extended quiescent state. - tick_nohz_irq_exit() which only updates the dynticks idle mode when ts->inidle is set (ie: if tick_nohz_idle_enter() has been called). To maintain symmetry, tick_nohz_restart_sched_tick() has been renamed into tick_nohz_idle_exit(). This simplifies the code and micro-optimize the irq exit path (no need for local_irq_save there). This also prepares for the split between dynticks and rcu extended quiescent state logics. We'll need this split to further fix illegal uses of RCU in extended quiescent states in the idle loop. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Mike Frysinger <vapier@gentoo.org> Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Cc: David Miller <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Paul Mackerras <paulus@samba.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-10-07 16:22:06 +00:00
return;
if (unlikely(local_softirq_pending() && cpu_online(cpu))) {
static int ratelimit;
if (ratelimit < 10) {
printk(KERN_ERR "NOHZ: local_softirq_pending %02x\n",
(unsigned int) local_softirq_pending());
ratelimit++;
}
nohz: Separate out irq exit and idle loop dyntick logic The tick_nohz_stop_sched_tick() function, which tries to delay the next timer tick as long as possible, can be called from two places: - From the idle loop to start the dytick idle mode - From interrupt exit if we have interrupted the dyntick idle mode, so that we reprogram the next tick event in case the irq changed some internal state that requires this action. There are only few minor differences between both that are handled by that function, driven by the ts->inidle cpu variable and the inidle parameter. The whole guarantees that we only update the dyntick mode on irq exit if we actually interrupted the dyntick idle mode, and that we enter in RCU extended quiescent state from idle loop entry only. Split this function into: - tick_nohz_idle_enter(), which sets ts->inidle to 1, enters dynticks idle mode unconditionally if it can, and enters into RCU extended quiescent state. - tick_nohz_irq_exit() which only updates the dynticks idle mode when ts->inidle is set (ie: if tick_nohz_idle_enter() has been called). To maintain symmetry, tick_nohz_restart_sched_tick() has been renamed into tick_nohz_idle_exit(). This simplifies the code and micro-optimize the irq exit path (no need for local_irq_save there). This also prepares for the split between dynticks and rcu extended quiescent state logics. We'll need this split to further fix illegal uses of RCU in extended quiescent states in the idle loop. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Mike Frysinger <vapier@gentoo.org> Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Cc: David Miller <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Paul Mackerras <paulus@samba.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-10-07 16:22:06 +00:00
return;
}
ts->idle_calls++;
/* Read jiffies and the time when jiffies were updated last */
do {
seq = read_seqbegin(&xtime_lock);
last_update = last_jiffies_update;
last_jiffies = jiffies;
time_delta = timekeeping_max_deferment();
} while (read_seqretry(&xtime_lock, seq));
if (rcu_needs_cpu(cpu) || printk_needs_cpu(cpu) ||
arch_needs_cpu(cpu)) {
next_jiffies = last_jiffies + 1;
delta_jiffies = 1;
} else {
/* Get the next timer wheel timer */
next_jiffies = get_next_timer_interrupt(last_jiffies);
delta_jiffies = next_jiffies - last_jiffies;
}
/*
* Do not stop the tick, if we are only one off
* or if the cpu is required for rcu
*/
if (!ts->tick_stopped && delta_jiffies == 1)
goto out;
/* Schedule the tick, if we are at least one jiffie off */
if ((long)delta_jiffies >= 1) {
/*
* If this cpu is the one which updates jiffies, then
* give up the assignment and let it be taken by the
* cpu which runs the tick timer next, which might be
* this cpu as well. If we don't drop this here the
* jiffies might be stale and do_timer() never
* invoked. Keep track of the fact that it was the one
* which had the do_timer() duty last. If this cpu is
* the one which had the do_timer() duty last, we
* limit the sleep time to the timekeeping
* max_deferement value which we retrieved
* above. Otherwise we can sleep as long as we want.
*/
if (cpu == tick_do_timer_cpu) {
tick_do_timer_cpu = TICK_DO_TIMER_NONE;
ts->do_timer_last = 1;
} else if (tick_do_timer_cpu != TICK_DO_TIMER_NONE) {
time_delta = KTIME_MAX;
ts->do_timer_last = 0;
} else if (!ts->do_timer_last) {
time_delta = KTIME_MAX;
}
/*
* calculate the expiry time for the next timer wheel
* timer. delta_jiffies >= NEXT_TIMER_MAX_DELTA signals
* that there is no timer pending or at least extremely
* far into the future (12 days for HZ=1000). In this
* case we set the expiry to the end of time.
*/
if (likely(delta_jiffies < NEXT_TIMER_MAX_DELTA)) {
/*
* Calculate the time delta for the next timer event.
* If the time delta exceeds the maximum time delta
* permitted by the current clocksource then adjust
* the time delta accordingly to ensure the
* clocksource does not wrap.
*/
time_delta = min_t(u64, time_delta,
tick_period.tv64 * delta_jiffies);
}
if (time_delta < KTIME_MAX)
expires = ktime_add_ns(last_update, time_delta);
else
expires.tv64 = KTIME_MAX;
/* Skip reprogram of event if its not changed */
if (ts->tick_stopped && ktime_equal(expires, dev->next_event))
goto out;
/*
* nohz_stop_sched_tick can be called several times before
* the nohz_restart_sched_tick is called. This happens when
* interrupts arrive which do not cause a reschedule. In the
* first call we save the current tick time, so we can restart
* the scheduler tick in nohz_restart_sched_tick.
*/
if (!ts->tick_stopped) {
sched: Change nohz idle load balancing logic to push model In the new push model, all idle CPUs indeed go into nohz mode. There is still the concept of idle load balancer (performing the load balancing on behalf of all the idle cpu's in the system). Busy CPU kicks the nohz balancer when any of the nohz CPUs need idle load balancing. The kickee CPU does the idle load balancing on behalf of all idle CPUs instead of the normal idle balance. This addresses the below two problems with the current nohz ilb logic: * the idle load balancer continued to have periodic ticks during idle and wokeup frequently, even though it did not have any rebalancing to do on behalf of any of the idle CPUs. * On x86 and CPUs that have APIC timer stoppage on idle CPUs, this periodic wakeup can result in a periodic additional interrupt on a CPU doing the timer broadcast. Also currently we are migrating the unpinned timers from an idle to the cpu doing idle load balancing (when all the cpus in the system are idle, there is no idle load balancing cpu and timers get added to the same idle cpu where the request was made. So the existing optimization works only on semi idle system). And In semi idle system, we no longer have periodic ticks on the idle load balancer CPU. Using that cpu will add more delays to the timers than intended (as that cpu's timer base may not be uptodate wrt jiffies etc). This was causing mysterious slowdowns during boot etc. For now, in the semi idle case, use the nearest busy cpu for migrating timers from an idle cpu. This is good for power-savings anyway. Signed-off-by: Venkatesh Pallipadi <venki@google.com> Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> LKML-Reference: <1274486981.2840.46.camel@sbs-t61.sc.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-05-22 00:09:41 +00:00
select_nohz_load_balancer(1);
ts->idle_tick = hrtimer_get_expires(&ts->sched_timer);
ts->tick_stopped = 1;
}
ts->idle_sleeps++;
/* Mark expires */
ts->idle_expires = expires;
/*
* If the expiration time == KTIME_MAX, then
* in this case we simply stop the tick timer.
*/
if (unlikely(expires.tv64 == KTIME_MAX)) {
if (ts->nohz_mode == NOHZ_MODE_HIGHRES)
hrtimer_cancel(&ts->sched_timer);
goto out;
}
if (ts->nohz_mode == NOHZ_MODE_HIGHRES) {
hrtimer_start(&ts->sched_timer, expires,
HRTIMER_MODE_ABS_PINNED);
/* Check, if the timer was already in the past */
if (hrtimer_active(&ts->sched_timer))
goto out;
} else if (!tick_program_event(expires, 0))
goto out;
/*
* We are past the event already. So we crossed a
* jiffie boundary. Update jiffies and raise the
* softirq.
*/
tick_do_update_jiffies64(ktime_get());
}
raise_softirq_irqoff(TIMER_SOFTIRQ);
out:
ts->next_jiffies = next_jiffies;
ts->last_jiffies = last_jiffies;
cpuidle: consolidate 2.6.22 cpuidle branch into one patch commit e5a16b1f9eec0af7cfa0830304b41c1c0833cf9f Author: Len Brown <len.brown@intel.com> Date: Tue Oct 2 23:44:44 2007 -0400 cpuidle: shrink diff processor_idle.c | 440 +++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 429 insertions(+), 11 deletions(-) Signed-off-by: Len Brown <len.brown@intel.com> commit dfbb9d5aedfb18848a3e0d6f6e3e4969febb209c Author: Len Brown <len.brown@intel.com> Date: Wed Sep 26 02:17:55 2007 -0400 cpuidle: reduce diff size Reduces the cpuidle processor_idle.c diff vs 2.6.22 from this processor_idle.c | 2006 ++++++++++++++++++++++++++----------------- 1 file changed, 1219 insertions(+), 787 deletions(-) to this: processor_idle.c | 502 +++++++++++++++++++++++++++++++++++++++---- 1 file changed, 458 insertions(+), 44 deletions(-) ...for the purpose of making the cpuilde patch less invasive and easier to review. no functional changes. build tested only. Signed-off-by: Len Brown <len.brown@intel.com> commit 889172fc915f5a7fe20f35b133cbd205ce69bf6c Author: Venki Pallipadi <venkatesh.pallipadi@intel.com> Date: Thu Sep 13 13:40:05 2007 -0700 cpuidle: Retain old ACPI policy for !CONFIG_CPU_IDLE Retain the old policy in processor_idle, so that when CPU_IDLE is not configured, old C-state policy will still be used. This provides a clean gradual migration path from old ACPI policy to new cpuidle based policy. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> commit 9544a8181edc7ecc33b3bfd69271571f98ed08bc Author: Venki Pallipadi <venkatesh.pallipadi@intel.com> Date: Thu Sep 13 13:39:17 2007 -0700 cpuidle: Configure governors by default Quoting Len "Do not give an option to users to shoot themselves in the foot". Remove the configurability of ladder and menu governors as they are needed for default policy of cpuidle. That way users will not be able to have cpuidle without any policy loosing all C-state power savings. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> commit 8975059a2c1e56cfe83d1bcf031bcf4cb39be743 Author: Adam Belay <abelay@novell.com> Date: Tue Aug 21 18:27:07 2007 -0400 CPUIDLE: load ACPI properly when CPUIDLE is disabled Change the registration return codes for when CPUIDLE support is not compiled into the kernel. As a result, the ACPI processor driver will load properly even if CPUIDLE is unavailable. However, it may be possible to cleanup the ACPI processor driver further and eliminate some dead code paths. Signed-off-by: Adam Belay <abelay@novell.com> Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> commit e0322e2b58dd1b12ec669bf84693efe0dc2414a8 Author: Adam Belay <abelay@novell.com> Date: Tue Aug 21 18:26:06 2007 -0400 CPUIDLE: remove cpuidle_get_bm_activity() Remove cpuidle_get_bm_activity() and updates governors accordingly. Signed-off-by: Adam Belay <abelay@novell.com> Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> commit 18a6e770d5c82ba26653e53d240caa617e09e9ab Author: Adam Belay <abelay@novell.com> Date: Tue Aug 21 18:25:58 2007 -0400 CPUIDLE: max_cstate fix Currently max_cstate is limited to 0, resulting in no idle processor power management on ACPI platforms. This patch restores the value to the array size. Signed-off-by: Adam Belay <abelay@novell.com> Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> commit 1fdc0887286179b40ce24bcdbde663172e205ef0 Author: Adam Belay <abelay@novell.com> Date: Tue Aug 21 18:25:40 2007 -0400 CPUIDLE: handle BM detection inside the ACPI Processor driver Update the ACPI processor driver to detect BM activity and limit state entry depth internally, rather than exposing such requirements to CPUIDLE. As a result, CPUIDLE can drop this ACPI-specific interface and become more platform independent. BM activity is now handled much more aggressively than it was in the original implementation, so some testing coverage may be needed to verify that this doesn't introduce any DMA buffer under-run issues. Signed-off-by: Adam Belay <abelay@novell.com> Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> commit 0ef38840db666f48e3cdd2b769da676c57228dd9 Author: Adam Belay <abelay@novell.com> Date: Tue Aug 21 18:25:14 2007 -0400 CPUIDLE: menu governor updates Tweak the menu governor to more effectively handle non-timer break events. Non-timer break events are detected by comparing the actual sleep time to the expected sleep time. In future revisions, it may be more reliable to use the timer data structures directly. Signed-off-by: Adam Belay <abelay@novell.com> Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> commit bb4d74fca63fa96cf3ace644b15ae0f12b7df5a1 Author: Adam Belay <abelay@novell.com> Date: Tue Aug 21 18:24:40 2007 -0400 CPUIDLE: fix 'current_governor' sysfs entry Allow the "current_governor" sysfs entry to properly handle input terminated with '\n'. Signed-off-by: Adam Belay <abelay@novell.com> Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> commit df3c71559bb69b125f1a48971bf0d17f78bbdf47 Author: Len Brown <len.brown@intel.com> Date: Sun Aug 12 02:00:45 2007 -0400 cpuidle: fix IA64 build (again) Signed-off-by: Len Brown <len.brown@intel.com> commit a02064579e3f9530fd31baae16b1fc46b5a7bca8 Author: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Date: Sun Aug 12 01:39:27 2007 -0400 cpuidle: Remove support for runtime changing of max_cstate Remove support for runtime changeability of max_cstate. Drivers can use use latency APIs. max_cstate can still be used as a boot time option and dmi override. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> commit 0912a44b13adf22f5e3f607d263aed23b4910d7e Author: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Date: Sun Aug 12 01:39:16 2007 -0400 cpuidle: Remove ACPI cstate_limit calls from ipw2100 ipw2100 already has code to use accetable_latency interfaces to limit the C-state. Remove the calls to acpi_set_cstate_limit and acpi_get_cstate_limit as they are redundant. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> commit c649a76e76be6bff1fd770d0a775798813a3f6e0 Author: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Date: Sun Aug 12 01:35:39 2007 -0400 cpuidle: compile fix for pause and resume functions Fix the compilation failure when cpuidle is not compiled in. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Acked-by: Adam Belay <adam.belay@novell.com> Signed-off-by: Len Brown <len.brown@intel.com> commit 2305a5920fb8ee6ccec1c62ade05aa8351091d71 Author: Adam Belay <abelay@novell.com> Date: Thu Jul 19 00:49:00 2007 -0400 cpuidle: re-write Some portions have been rewritten to make the code cleaner and lighter weight. The following is a list of changes: 1.) the state name is now included in the sysfs interface 2.) detection, hotplug, and available state modifications are handled by CPUIDLE drivers directly 3.) the CPUIDLE idle handler is only ever installed when at least one cpuidle_device is enabled and ready 4.) the menu governor BM code no longer overflows 5.) the sysfs attributes are now printed as unsigned integers, avoiding negative values 6.) a variety of other small cleanups Also, Idle drivers are no longer swappable during runtime through the CPUIDLE sysfs inteface. On i386 and x86_64 most idle handlers (e.g. poll, mwait, halt, etc.) don't benefit from an infrastructure that supports multiple states, so I think using a more general case idle handler selection mechanism would be cleaner. Signed-off-by: Adam Belay <abelay@novell.com> Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Acked-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> commit df25b6b56955714e6e24b574d88d1fd11f0c3ee5 Author: Len Brown <len.brown@intel.com> Date: Tue Jul 24 17:08:21 2007 -0400 cpuidle: fix IA64 buid Signed-off-by: Len Brown <len.brown@intel.com> commit fd6ada4c14488755ff7068860078c437431fbccd Author: Adrian Bunk <bunk@stusta.de> Date: Mon Jul 9 11:33:13 2007 -0700 cpuidle: static make cpuidle_replace_governor() static Signed-off-by: Adrian Bunk <bunk@stusta.de> Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit c1d4a2cebcadf2429c0c72e1d29aa2a9684c32e0 Author: Adrian Bunk <bunk@stusta.de> Date: Tue Jul 3 00:54:40 2007 -0400 cpuidle: static This patch makes the needlessly global struct menu_governor static. Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit dbf8780c6e8d572c2c273da97ed1cca7608fd999 Author: Andrew Morton <akpm@linux-foundation.org> Date: Tue Jul 3 00:49:14 2007 -0400 export symbol tick_nohz_get_sleep_length ERROR: "tick_nohz_get_sleep_length" [drivers/cpuidle/governors/menu.ko] undefined! ERROR: "tick_nohz_get_idle_jiffies" [drivers/cpuidle/governors/menu.ko] undefined! And please be sure to get your changes to core kernel suitably reviewed. Cc: Adam Belay <abelay@novell.com> Cc: Venki Pallipadi <venkatesh.pallipadi@intel.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: john stultz <johnstul@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit 29f0e248e7017be15f99febf9143a2cef00b2961 Author: Andrew Morton <akpm@linux-foundation.org> Date: Tue Jul 3 00:43:04 2007 -0400 tick.h needs hrtimer.h It uses hrtimers. Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit e40cede7d63a029e92712a3fe02faee60cc38fb4 Author: Venki Pallipadi <venkatesh.pallipadi@intel.com> Date: Tue Jul 3 00:40:34 2007 -0400 cpuidle: first round of documentation updates Documentation changes based on Pavel's feedback. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit 83b42be2efece386976507555c29e7773a0dfcd1 Author: Venki Pallipadi <venkatesh.pallipadi@intel.com> Date: Tue Jul 3 00:39:25 2007 -0400 cpuidle: add rating to the governors and pick the one with highest rating by default Introduce a governor rating scheme to pick the right governor by default. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit d2a74b8c5e8f22def4709330d4bfc4a29209b71c Author: Venki Pallipadi <venkatesh.pallipadi@intel.com> Date: Tue Jul 3 00:38:08 2007 -0400 cpuidle: make cpuidle sysfs driver governor switch off by default Make default cpuidle sysfs to show current_governor and current_driver in read-only mode. More elaborate available_governors and available_drivers with writeable current_governor and current_driver interface only appear with "cpuidle_sysfs_switch" boot parameter. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit 1f60a0e80bf83cf6b55c8845bbe5596ed8f6307b Author: Venki Pallipadi <venkatesh.pallipadi@intel.com> Date: Tue Jul 3 00:37:00 2007 -0400 cpuidle: menu governor: change the early break condition Change the C-state early break out algorithm in menu governor. We only look at early breakouts that result in wakeups shorter than idle state's target_residency. If such a breakout is frequent enough, eliminate the particular idle state upto a timeout period. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit 45a42095cf64b003b4a69be3ce7f434f97d7af51 Author: Venki Pallipadi <venkatesh.pallipadi@intel.com> Date: Tue Jul 3 00:35:38 2007 -0400 cpuidle: fix uninitialized variable in sysfs routine Fix the uninitialized usage of ret. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit 80dca7cdba3e6ee13eae277660873ab9584eb3be Author: Venki Pallipadi <venkatesh.pallipadi@intel.com> Date: Tue Jul 3 00:34:16 2007 -0400 cpuidle: reenable /proc/acpi//power interface for the time being Keep /proc/acpi/processor/CPU*/power around for a while as powertop depends on it. It will be marked deprecated and removed in future. powertop can use cpuidle interfaces instead. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit 589c37c2646c5e3813a51255a5ee1159cb4c33fc Author: Venki Pallipadi <venkatesh.pallipadi@intel.com> Date: Tue Jul 3 00:32:37 2007 -0400 cpuidle: menu governor and hrtimer compile fix Compile fix for menu governor. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit 0ba80bd9ab3ed304cb4f19b722e4cc6740588b5e Author: Len Brown <len.brown@intel.com> Date: Thu May 31 22:51:43 2007 -0400 cpuidle: build fix - cpuidle vs ipw2100 module ERROR: "acpi_set_cstate_limit" [drivers/net/wireless/ipw2100.ko] undefined! Signed-off-by: Len Brown <len.brown@intel.com> commit d7d8fa7f96a7f7682be7c6cc0cc53fa7a18c3b58 Author: Adam Belay <abelay@novell.com> Date: Sat Mar 24 03:47:07 2007 -0400 cpuidle: add the 'menu' governor Here is my first take at implementing an idle PM governor that takes full advantage of NO_HZ. I call it the 'menu' governor because it considers the full list of idle states before each entry. I've kept the implementation fairly simple. It attempts to guess the next residency time and then chooses a state that would meet at least the break-even point between power savings and entry cost. To this end, it selects the deepest idle state that satisfies the following constraints: 1. If the idle time elapsed since bus master activity was detected is below a threshold (currently 20 ms), then limit the selection to C2-type or above. 2. Do not choose a state with a break-even residency that exceeds the expected time remaining until the next timer interrupt. 3. Do not choose a state with a break-even residency that exceeds the elapsed time between the last pair of break events, excluding timer interrupts. This governor has an advantage over "ladder" governor because it proactively checks how much time remains until the next timer interrupt using the tick infrastructure. Also, it handles device interrupt activity more intelligently by not including timer interrupts in break event calculations. Finally, it doesn't make policy decisions using the number of state entries, which can have variable residency times (NO_HZ makes these potentially very large), and instead only considers sleep time deltas. The menu governor can be selected during runtime using the cpuidle sysfs interface like so: "echo "menu" > /sys/devices/system/cpu/cpuidle/current_governor" Signed-off-by: Adam Belay <abelay@novell.com> Signed-off-by: Len Brown <len.brown@intel.com> commit a4bec7e65aa3b7488b879d971651cc99a6c410fe Author: Adam Belay <abelay@novell.com> Date: Sat Mar 24 03:47:03 2007 -0400 cpuidle: export time until next timer interrupt using NO_HZ Expose information about the time remaining until the next timer interrupt expires by utilizing the dynticks infrastructure. Also modify the main idle loop to allow dynticks to handle non-interrupt break events (e.g. DMA). Finally, expose sleep ticks information to external code. Thomas Gleixner is responsible for much of the code in this patch. However, I've made some additional changes, so I'm probably responsible if there are any bugs or oversights :) Signed-off-by: Adam Belay <abelay@novell.com> Signed-off-by: Len Brown <len.brown@intel.com> commit 2929d8996fbc77f41a5ff86bb67cdde3ca7d2d72 Author: Adam Belay <abelay@novell.com> Date: Sat Mar 24 03:46:58 2007 -0400 cpuidle: governor API changes This patch prepares cpuidle for the menu governor. It adds an optional stage after idle state entry to give the governor an opportunity to check why the state was exited. Also it makes sure the idle loop returns after each state entry, allowing the appropriate dynticks code to run. Signed-off-by: Adam Belay <abelay@novell.com> Signed-off-by: Len Brown <len.brown@intel.com> commit 3a7fd42f9825c3b03e364ca59baa751bb350775f Author: Venki Pallipadi <venkatesh.pallipadi@intel.com> Date: Thu Apr 26 00:03:59 2007 -0700 cpuidle: hang fix Prevent hang on x86-64, when ACPI processor driver is added as a module on a system that does not support C-states. x86-64 expects all idle handlers to enable interrupts before returning from idle handler. This is due to enter_idle(), exit_idle() races. Make cpuidle_idle_call() confirm to this when there is no pm_idle_old. Also, cpuidle look at the return values of attch_driver() and set current_driver to NULL if attach fails on all CPUs. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit 4893339a142afbd5b7c01ffadfd53d14746e858e Author: Shaohua Li <shaohua.li@intel.com> Date: Thu Apr 26 10:40:09 2007 +0800 cpuidle: add support for max_cstate limit With CPUIDLE framework, the max_cstate (to limit max cpu c-state) parameter is ingored. Some systems require it to ignore C2/C3 and some drivers like ipw require it too. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> commit 43bbbbe1cb998cbd2df656f55bb3bfe30f30e7d1 Author: Shaohua Li <shaohua.li@intel.com> Date: Thu Apr 26 10:40:13 2007 +0800 cpuidle: add cpuidle_fore_redetect_devices API add cpuidle_force_redetect_devices API, which forces all CPU redetect idle states. Next patch will use it. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> commit d1edadd608f24836def5ec483d2edccfb37b1d19 Author: Shaohua Li <shaohua.li@intel.com> Date: Thu Apr 26 10:40:01 2007 +0800 cpuidle: fix sysfs related issue Fix the cpuidle sysfs issue. a. make kobject dynamicaly allocated b. fixed sysfs init issue to avoid suspend/resume issue Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> commit 7169a5cc0d67b263978859672e86c13c23a5570d Author: Randy Dunlap <randy.dunlap@oracle.com> Date: Wed Mar 28 22:52:53 2007 -0400 cpuidle: 1-bit field must be unsigned A 1-bit bitfield has no room for a sign bit. drivers/cpuidle/governors/ladder.c:54:16: error: dubious bitfield without explicit `signed' or `unsigned' Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit 4658620158dc2fbd9e4bcb213c5b6fb5d05ba7d4 Author: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Date: Wed Mar 28 22:52:41 2007 -0400 cpuidle: fix boot hang Patch for cpuidle boot hang reported by Larry Finger here. http://www.ussg.iu.edu/hypermail/linux/kernel/0703.2/2025.html Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Cc: Larry Finger <larry.finger@lwfinger.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit c17e168aa6e5fe3851baaae8df2fbc1cf11443a9 Author: Len Brown <len.brown@intel.com> Date: Wed Mar 7 04:37:53 2007 -0500 cpuidle: ladder does not depend on ACPI build fix for CONFIG_ACPI=n In file included from drivers/cpuidle/governors/ladder.c:21: include/acpi/processor.h:88: error: expected specifier-qualifier-list before ‘acpi_integer’ include/acpi/processor.h:106: error: expected specifier-qualifier-list before ‘acpi_integer’ include/acpi/processor.h:168: error: expected specifier-qualifier-list before ‘acpi_handle’ Signed-off-by: Len Brown <len.brown@intel.com> commit 8c91d958246bde68db0c3f0c57b535962ce861cb Author: Adrian Bunk <bunk@stusta.de> Date: Tue Mar 6 02:29:40 2007 -0800 cpuidle: make code static This patch makes the following needlessly global code static: - driver.c: __cpuidle_find_driver() - governor.c: __cpuidle_find_governor() - ladder.c: struct ladder_governor Signed-off-by: Adrian Bunk <bunk@stusta.de> Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Cc: Adam Belay <abelay@novell.com> Cc: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit 0c39dc3187094c72c33ab65a64d2017b21f372d2 Author: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Date: Wed Mar 7 02:38:22 2007 -0500 cpu_idle: fix build break This patch fixes a build breakage with !CONFIG_HOTPLUG_CPU and CONFIG_CPU_IDLE. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit 8112e3b115659b07df340ef170515799c0105f82 Author: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Date: Tue Mar 6 02:29:39 2007 -0800 cpuidle: build fix for !CPU_IDLE Fix the compile issues when CPU_IDLE is not configured. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Cc: Adam Belay <abelay@novell.com> Cc: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit 1eb4431e9599cd25e0d9872f3c2c8986821839dd Author: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Date: Thu Feb 22 13:54:57 2007 -0800 cpuidle take2: Basic documentation for cpuidle Documentation for cpuidle infrastructure Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Adam Belay <abelay@novell.com> Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> commit ef5f15a8b79123a047285ec2e3899108661df779 Author: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Date: Thu Feb 22 13:54:03 2007 -0800 cpuidle take2: Hookup ACPI C-states driver with cpuidle Hookup ACPI C-states onto generic cpuidle infrastructure. drivers/acpi/procesor_idle.c is now a ACPI C-states driver that registers as a driver in cpuidle infrastructure and the policy part is removed from drivers/acpi/processor_idle.c. We use governor in cpuidle instead. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Adam Belay <abelay@novell.com> Signed-off-by: Len Brown <len.brown@intel.com> commit 987196fa82d4db52c407e8c9d5dec884ba602183 Author: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Date: Thu Feb 22 13:52:57 2007 -0800 cpuidle take2: Core cpuidle infrastructure Announcing 'cpuidle', a new CPU power management infrastructure to manage idle CPUs in a clean and efficient manner. cpuidle separates out the drivers that can provide support for multiple types of idle states and policy governors that decide on what idle state to use at run time. A cpuidle driver can support multiple idle states based on parameters like varying power consumption, wakeup latency, etc (ACPI C-states for example). A cpuidle governor can be usage model specific (laptop, server, laptop on battery etc). Main advantage of the infrastructure being, it allows independent development of drivers and governors and allows for better CPU power management. A huge thanks to Adam Belay and Shaohua Li who were part of this mini-project since its beginning and are greatly responsible for this patchset. This patch: Core cpuidle infrastructure. Introduces a new abstraction layer for cpuidle: * which manages drivers that can support multiple idles states. Drivers can be generic or particular to specific hardware/platform * allows pluging in multiple policy governors that can take idle state policy decision * The core also has a set of sysfs interfaces with which administrato can know about supported drivers and governors and switch them at run time. Signed-off-by: Adam Belay <abelay@novell.com> Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> Signed-off-by: Len Brown <len.brown@intel.com>
2007-10-03 22:58:00 +00:00
ts->sleep_length = ktime_sub(dev->next_event, now);
nohz: Separate out irq exit and idle loop dyntick logic The tick_nohz_stop_sched_tick() function, which tries to delay the next timer tick as long as possible, can be called from two places: - From the idle loop to start the dytick idle mode - From interrupt exit if we have interrupted the dyntick idle mode, so that we reprogram the next tick event in case the irq changed some internal state that requires this action. There are only few minor differences between both that are handled by that function, driven by the ts->inidle cpu variable and the inidle parameter. The whole guarantees that we only update the dyntick mode on irq exit if we actually interrupted the dyntick idle mode, and that we enter in RCU extended quiescent state from idle loop entry only. Split this function into: - tick_nohz_idle_enter(), which sets ts->inidle to 1, enters dynticks idle mode unconditionally if it can, and enters into RCU extended quiescent state. - tick_nohz_irq_exit() which only updates the dynticks idle mode when ts->inidle is set (ie: if tick_nohz_idle_enter() has been called). To maintain symmetry, tick_nohz_restart_sched_tick() has been renamed into tick_nohz_idle_exit(). This simplifies the code and micro-optimize the irq exit path (no need for local_irq_save there). This also prepares for the split between dynticks and rcu extended quiescent state logics. We'll need this split to further fix illegal uses of RCU in extended quiescent states in the idle loop. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Mike Frysinger <vapier@gentoo.org> Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Cc: David Miller <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Paul Mackerras <paulus@samba.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-10-07 16:22:06 +00:00
}
static void __tick_nohz_idle_enter(struct tick_sched *ts)
{
ktime_t now;
nohz: Make nohz API agnostic against idle ticks cputime accounting When the timer tick fires, it accounts the new jiffy as either part of system, user or idle time. This is how we record the cputime statistics. But when the tick is stopped from the idle task, we still need to record the number of jiffies spent tickless until we restart the tick and fall back to traditional tick-based cputime accounting. To do this, we take a snapshot of jiffies when the tick is stopped and compute the difference against the new value of jiffies when the tick is restarted. Then we account this whole difference to the idle cputime. However we are preparing to be able to stop the tick from other places than idle. So this idle time accounting needs to be performed from the callers of nohz APIs, not from the nohz APIs themselves because we now want them to be agnostic against places that stop/restart tick. Therefore, we pull the tickless idle time accounting out of generic nohz helpers up to idle entry/exit callers. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Alessio Igor Bogani <abogani@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Avi Kivity <avi@redhat.com> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Christoph Lameter <cl@linux.com> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Geoff Levand <geoff@infradead.org> Cc: Gilad Ben Yossef <gilad@benyossef.com> Cc: Hakan Akkan <hakanakkan@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Kevin Hilman <khilman@ti.com> Cc: Max Krasnyansky <maxk@qualcomm.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephen Hemminger <shemminger@vyatta.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Sven-Thorsten Dietrich <thebigcorporation@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de>
2011-07-28 02:00:47 +00:00
int was_stopped = ts->tick_stopped;
now = tick_nohz_start_idle(smp_processor_id(), ts);
tick_nohz_stop_sched_tick(ts, now);
nohz: Make nohz API agnostic against idle ticks cputime accounting When the timer tick fires, it accounts the new jiffy as either part of system, user or idle time. This is how we record the cputime statistics. But when the tick is stopped from the idle task, we still need to record the number of jiffies spent tickless until we restart the tick and fall back to traditional tick-based cputime accounting. To do this, we take a snapshot of jiffies when the tick is stopped and compute the difference against the new value of jiffies when the tick is restarted. Then we account this whole difference to the idle cputime. However we are preparing to be able to stop the tick from other places than idle. So this idle time accounting needs to be performed from the callers of nohz APIs, not from the nohz APIs themselves because we now want them to be agnostic against places that stop/restart tick. Therefore, we pull the tickless idle time accounting out of generic nohz helpers up to idle entry/exit callers. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Alessio Igor Bogani <abogani@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Avi Kivity <avi@redhat.com> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Christoph Lameter <cl@linux.com> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Geoff Levand <geoff@infradead.org> Cc: Gilad Ben Yossef <gilad@benyossef.com> Cc: Hakan Akkan <hakanakkan@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Kevin Hilman <khilman@ti.com> Cc: Max Krasnyansky <maxk@qualcomm.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephen Hemminger <shemminger@vyatta.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Sven-Thorsten Dietrich <thebigcorporation@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de>
2011-07-28 02:00:47 +00:00
if (!was_stopped && ts->tick_stopped)
ts->idle_jiffies = ts->last_jiffies;
}
nohz: Separate out irq exit and idle loop dyntick logic The tick_nohz_stop_sched_tick() function, which tries to delay the next timer tick as long as possible, can be called from two places: - From the idle loop to start the dytick idle mode - From interrupt exit if we have interrupted the dyntick idle mode, so that we reprogram the next tick event in case the irq changed some internal state that requires this action. There are only few minor differences between both that are handled by that function, driven by the ts->inidle cpu variable and the inidle parameter. The whole guarantees that we only update the dyntick mode on irq exit if we actually interrupted the dyntick idle mode, and that we enter in RCU extended quiescent state from idle loop entry only. Split this function into: - tick_nohz_idle_enter(), which sets ts->inidle to 1, enters dynticks idle mode unconditionally if it can, and enters into RCU extended quiescent state. - tick_nohz_irq_exit() which only updates the dynticks idle mode when ts->inidle is set (ie: if tick_nohz_idle_enter() has been called). To maintain symmetry, tick_nohz_restart_sched_tick() has been renamed into tick_nohz_idle_exit(). This simplifies the code and micro-optimize the irq exit path (no need for local_irq_save there). This also prepares for the split between dynticks and rcu extended quiescent state logics. We'll need this split to further fix illegal uses of RCU in extended quiescent states in the idle loop. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Mike Frysinger <vapier@gentoo.org> Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Cc: David Miller <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Paul Mackerras <paulus@samba.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-10-07 16:22:06 +00:00
/**
* tick_nohz_idle_enter - stop the idle tick from the idle task
*
* When the next event is more than a tick into the future, stop the idle tick
* Called when we start the idle loop.
nohz: Allow rcu extended quiescent state handling seperately from tick stop It is assumed that rcu won't be used once we switch to tickless mode and until we restart the tick. However this is not always true, as in x86-64 where we dereference the idle notifiers after the tick is stopped. To prepare for fixing this, add two new APIs: tick_nohz_idle_enter_norcu() and tick_nohz_idle_exit_norcu(). If no use of RCU is made in the idle loop between tick_nohz_enter_idle() and tick_nohz_exit_idle() calls, the arch must instead call the new *_norcu() version such that the arch doesn't need to call rcu_idle_enter() and rcu_idle_exit(). Otherwise the arch must call tick_nohz_enter_idle() and tick_nohz_exit_idle() and also call explicitly: - rcu_idle_enter() after its last use of RCU before the CPU is put to sleep. - rcu_idle_exit() before the first use of RCU after the CPU is woken up. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Mike Frysinger <vapier@gentoo.org> Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Cc: David Miller <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Paul Mackerras <paulus@samba.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2011-10-08 14:01:00 +00:00
*
* The arch is responsible of calling:
nohz: Allow rcu extended quiescent state handling seperately from tick stop It is assumed that rcu won't be used once we switch to tickless mode and until we restart the tick. However this is not always true, as in x86-64 where we dereference the idle notifiers after the tick is stopped. To prepare for fixing this, add two new APIs: tick_nohz_idle_enter_norcu() and tick_nohz_idle_exit_norcu(). If no use of RCU is made in the idle loop between tick_nohz_enter_idle() and tick_nohz_exit_idle() calls, the arch must instead call the new *_norcu() version such that the arch doesn't need to call rcu_idle_enter() and rcu_idle_exit(). Otherwise the arch must call tick_nohz_enter_idle() and tick_nohz_exit_idle() and also call explicitly: - rcu_idle_enter() after its last use of RCU before the CPU is put to sleep. - rcu_idle_exit() before the first use of RCU after the CPU is woken up. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Mike Frysinger <vapier@gentoo.org> Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Cc: David Miller <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Paul Mackerras <paulus@samba.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2011-10-08 14:01:00 +00:00
*
* - rcu_idle_enter() after its last use of RCU before the CPU is put
* to sleep.
* - rcu_idle_exit() before the first use of RCU after the CPU is woken up.
nohz: Separate out irq exit and idle loop dyntick logic The tick_nohz_stop_sched_tick() function, which tries to delay the next timer tick as long as possible, can be called from two places: - From the idle loop to start the dytick idle mode - From interrupt exit if we have interrupted the dyntick idle mode, so that we reprogram the next tick event in case the irq changed some internal state that requires this action. There are only few minor differences between both that are handled by that function, driven by the ts->inidle cpu variable and the inidle parameter. The whole guarantees that we only update the dyntick mode on irq exit if we actually interrupted the dyntick idle mode, and that we enter in RCU extended quiescent state from idle loop entry only. Split this function into: - tick_nohz_idle_enter(), which sets ts->inidle to 1, enters dynticks idle mode unconditionally if it can, and enters into RCU extended quiescent state. - tick_nohz_irq_exit() which only updates the dynticks idle mode when ts->inidle is set (ie: if tick_nohz_idle_enter() has been called). To maintain symmetry, tick_nohz_restart_sched_tick() has been renamed into tick_nohz_idle_exit(). This simplifies the code and micro-optimize the irq exit path (no need for local_irq_save there). This also prepares for the split between dynticks and rcu extended quiescent state logics. We'll need this split to further fix illegal uses of RCU in extended quiescent states in the idle loop. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Mike Frysinger <vapier@gentoo.org> Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Cc: David Miller <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Paul Mackerras <paulus@samba.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-10-07 16:22:06 +00:00
*/
void tick_nohz_idle_enter(void)
nohz: Separate out irq exit and idle loop dyntick logic The tick_nohz_stop_sched_tick() function, which tries to delay the next timer tick as long as possible, can be called from two places: - From the idle loop to start the dytick idle mode - From interrupt exit if we have interrupted the dyntick idle mode, so that we reprogram the next tick event in case the irq changed some internal state that requires this action. There are only few minor differences between both that are handled by that function, driven by the ts->inidle cpu variable and the inidle parameter. The whole guarantees that we only update the dyntick mode on irq exit if we actually interrupted the dyntick idle mode, and that we enter in RCU extended quiescent state from idle loop entry only. Split this function into: - tick_nohz_idle_enter(), which sets ts->inidle to 1, enters dynticks idle mode unconditionally if it can, and enters into RCU extended quiescent state. - tick_nohz_irq_exit() which only updates the dynticks idle mode when ts->inidle is set (ie: if tick_nohz_idle_enter() has been called). To maintain symmetry, tick_nohz_restart_sched_tick() has been renamed into tick_nohz_idle_exit(). This simplifies the code and micro-optimize the irq exit path (no need for local_irq_save there). This also prepares for the split between dynticks and rcu extended quiescent state logics. We'll need this split to further fix illegal uses of RCU in extended quiescent states in the idle loop. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Mike Frysinger <vapier@gentoo.org> Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Cc: David Miller <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Paul Mackerras <paulus@samba.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-10-07 16:22:06 +00:00
{
struct tick_sched *ts;
WARN_ON_ONCE(irqs_disabled());
/*
* Update the idle state in the scheduler domain hierarchy
* when tick_nohz_stop_sched_tick() is called from the idle loop.
* State will be updated to busy during the first busy tick after
* exiting idle.
*/
set_cpu_sd_state_idle();
local_irq_disable();
nohz: Separate out irq exit and idle loop dyntick logic The tick_nohz_stop_sched_tick() function, which tries to delay the next timer tick as long as possible, can be called from two places: - From the idle loop to start the dytick idle mode - From interrupt exit if we have interrupted the dyntick idle mode, so that we reprogram the next tick event in case the irq changed some internal state that requires this action. There are only few minor differences between both that are handled by that function, driven by the ts->inidle cpu variable and the inidle parameter. The whole guarantees that we only update the dyntick mode on irq exit if we actually interrupted the dyntick idle mode, and that we enter in RCU extended quiescent state from idle loop entry only. Split this function into: - tick_nohz_idle_enter(), which sets ts->inidle to 1, enters dynticks idle mode unconditionally if it can, and enters into RCU extended quiescent state. - tick_nohz_irq_exit() which only updates the dynticks idle mode when ts->inidle is set (ie: if tick_nohz_idle_enter() has been called). To maintain symmetry, tick_nohz_restart_sched_tick() has been renamed into tick_nohz_idle_exit(). This simplifies the code and micro-optimize the irq exit path (no need for local_irq_save there). This also prepares for the split between dynticks and rcu extended quiescent state logics. We'll need this split to further fix illegal uses of RCU in extended quiescent states in the idle loop. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Mike Frysinger <vapier@gentoo.org> Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Cc: David Miller <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Paul Mackerras <paulus@samba.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-10-07 16:22:06 +00:00
ts = &__get_cpu_var(tick_cpu_sched);
/*
* set ts->inidle unconditionally. even if the system did not
* switch to nohz mode the cpu frequency governers rely on the
* update of the idle time accounting in tick_nohz_start_idle().
*/
ts->inidle = 1;
__tick_nohz_idle_enter(ts);
local_irq_enable();
nohz: Separate out irq exit and idle loop dyntick logic The tick_nohz_stop_sched_tick() function, which tries to delay the next timer tick as long as possible, can be called from two places: - From the idle loop to start the dytick idle mode - From interrupt exit if we have interrupted the dyntick idle mode, so that we reprogram the next tick event in case the irq changed some internal state that requires this action. There are only few minor differences between both that are handled by that function, driven by the ts->inidle cpu variable and the inidle parameter. The whole guarantees that we only update the dyntick mode on irq exit if we actually interrupted the dyntick idle mode, and that we enter in RCU extended quiescent state from idle loop entry only. Split this function into: - tick_nohz_idle_enter(), which sets ts->inidle to 1, enters dynticks idle mode unconditionally if it can, and enters into RCU extended quiescent state. - tick_nohz_irq_exit() which only updates the dynticks idle mode when ts->inidle is set (ie: if tick_nohz_idle_enter() has been called). To maintain symmetry, tick_nohz_restart_sched_tick() has been renamed into tick_nohz_idle_exit(). This simplifies the code and micro-optimize the irq exit path (no need for local_irq_save there). This also prepares for the split between dynticks and rcu extended quiescent state logics. We'll need this split to further fix illegal uses of RCU in extended quiescent states in the idle loop. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Mike Frysinger <vapier@gentoo.org> Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Cc: David Miller <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Paul Mackerras <paulus@samba.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-10-07 16:22:06 +00:00
}
/**
* tick_nohz_irq_exit - update next tick event from interrupt exit
*
* When an interrupt fires while we are idle and it doesn't cause
* a reschedule, it may still add, modify or delete a timer, enqueue
* an RCU callback, etc...
* So we need to re-calculate and reprogram the next tick event.
*/
void tick_nohz_irq_exit(void)
{
struct tick_sched *ts = &__get_cpu_var(tick_cpu_sched);
if (!ts->inidle)
return;
__tick_nohz_idle_enter(ts);
}
cpuidle: consolidate 2.6.22 cpuidle branch into one patch commit e5a16b1f9eec0af7cfa0830304b41c1c0833cf9f Author: Len Brown <len.brown@intel.com> Date: Tue Oct 2 23:44:44 2007 -0400 cpuidle: shrink diff processor_idle.c | 440 +++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 429 insertions(+), 11 deletions(-) Signed-off-by: Len Brown <len.brown@intel.com> commit dfbb9d5aedfb18848a3e0d6f6e3e4969febb209c Author: Len Brown <len.brown@intel.com> Date: Wed Sep 26 02:17:55 2007 -0400 cpuidle: reduce diff size Reduces the cpuidle processor_idle.c diff vs 2.6.22 from this processor_idle.c | 2006 ++++++++++++++++++++++++++----------------- 1 file changed, 1219 insertions(+), 787 deletions(-) to this: processor_idle.c | 502 +++++++++++++++++++++++++++++++++++++++---- 1 file changed, 458 insertions(+), 44 deletions(-) ...for the purpose of making the cpuilde patch less invasive and easier to review. no functional changes. build tested only. Signed-off-by: Len Brown <len.brown@intel.com> commit 889172fc915f5a7fe20f35b133cbd205ce69bf6c Author: Venki Pallipadi <venkatesh.pallipadi@intel.com> Date: Thu Sep 13 13:40:05 2007 -0700 cpuidle: Retain old ACPI policy for !CONFIG_CPU_IDLE Retain the old policy in processor_idle, so that when CPU_IDLE is not configured, old C-state policy will still be used. This provides a clean gradual migration path from old ACPI policy to new cpuidle based policy. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> commit 9544a8181edc7ecc33b3bfd69271571f98ed08bc Author: Venki Pallipadi <venkatesh.pallipadi@intel.com> Date: Thu Sep 13 13:39:17 2007 -0700 cpuidle: Configure governors by default Quoting Len "Do not give an option to users to shoot themselves in the foot". Remove the configurability of ladder and menu governors as they are needed for default policy of cpuidle. That way users will not be able to have cpuidle without any policy loosing all C-state power savings. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> commit 8975059a2c1e56cfe83d1bcf031bcf4cb39be743 Author: Adam Belay <abelay@novell.com> Date: Tue Aug 21 18:27:07 2007 -0400 CPUIDLE: load ACPI properly when CPUIDLE is disabled Change the registration return codes for when CPUIDLE support is not compiled into the kernel. As a result, the ACPI processor driver will load properly even if CPUIDLE is unavailable. However, it may be possible to cleanup the ACPI processor driver further and eliminate some dead code paths. Signed-off-by: Adam Belay <abelay@novell.com> Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> commit e0322e2b58dd1b12ec669bf84693efe0dc2414a8 Author: Adam Belay <abelay@novell.com> Date: Tue Aug 21 18:26:06 2007 -0400 CPUIDLE: remove cpuidle_get_bm_activity() Remove cpuidle_get_bm_activity() and updates governors accordingly. Signed-off-by: Adam Belay <abelay@novell.com> Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> commit 18a6e770d5c82ba26653e53d240caa617e09e9ab Author: Adam Belay <abelay@novell.com> Date: Tue Aug 21 18:25:58 2007 -0400 CPUIDLE: max_cstate fix Currently max_cstate is limited to 0, resulting in no idle processor power management on ACPI platforms. This patch restores the value to the array size. Signed-off-by: Adam Belay <abelay@novell.com> Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> commit 1fdc0887286179b40ce24bcdbde663172e205ef0 Author: Adam Belay <abelay@novell.com> Date: Tue Aug 21 18:25:40 2007 -0400 CPUIDLE: handle BM detection inside the ACPI Processor driver Update the ACPI processor driver to detect BM activity and limit state entry depth internally, rather than exposing such requirements to CPUIDLE. As a result, CPUIDLE can drop this ACPI-specific interface and become more platform independent. BM activity is now handled much more aggressively than it was in the original implementation, so some testing coverage may be needed to verify that this doesn't introduce any DMA buffer under-run issues. Signed-off-by: Adam Belay <abelay@novell.com> Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> commit 0ef38840db666f48e3cdd2b769da676c57228dd9 Author: Adam Belay <abelay@novell.com> Date: Tue Aug 21 18:25:14 2007 -0400 CPUIDLE: menu governor updates Tweak the menu governor to more effectively handle non-timer break events. Non-timer break events are detected by comparing the actual sleep time to the expected sleep time. In future revisions, it may be more reliable to use the timer data structures directly. Signed-off-by: Adam Belay <abelay@novell.com> Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> commit bb4d74fca63fa96cf3ace644b15ae0f12b7df5a1 Author: Adam Belay <abelay@novell.com> Date: Tue Aug 21 18:24:40 2007 -0400 CPUIDLE: fix 'current_governor' sysfs entry Allow the "current_governor" sysfs entry to properly handle input terminated with '\n'. Signed-off-by: Adam Belay <abelay@novell.com> Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> commit df3c71559bb69b125f1a48971bf0d17f78bbdf47 Author: Len Brown <len.brown@intel.com> Date: Sun Aug 12 02:00:45 2007 -0400 cpuidle: fix IA64 build (again) Signed-off-by: Len Brown <len.brown@intel.com> commit a02064579e3f9530fd31baae16b1fc46b5a7bca8 Author: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Date: Sun Aug 12 01:39:27 2007 -0400 cpuidle: Remove support for runtime changing of max_cstate Remove support for runtime changeability of max_cstate. Drivers can use use latency APIs. max_cstate can still be used as a boot time option and dmi override. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> commit 0912a44b13adf22f5e3f607d263aed23b4910d7e Author: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Date: Sun Aug 12 01:39:16 2007 -0400 cpuidle: Remove ACPI cstate_limit calls from ipw2100 ipw2100 already has code to use accetable_latency interfaces to limit the C-state. Remove the calls to acpi_set_cstate_limit and acpi_get_cstate_limit as they are redundant. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> commit c649a76e76be6bff1fd770d0a775798813a3f6e0 Author: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Date: Sun Aug 12 01:35:39 2007 -0400 cpuidle: compile fix for pause and resume functions Fix the compilation failure when cpuidle is not compiled in. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Acked-by: Adam Belay <adam.belay@novell.com> Signed-off-by: Len Brown <len.brown@intel.com> commit 2305a5920fb8ee6ccec1c62ade05aa8351091d71 Author: Adam Belay <abelay@novell.com> Date: Thu Jul 19 00:49:00 2007 -0400 cpuidle: re-write Some portions have been rewritten to make the code cleaner and lighter weight. The following is a list of changes: 1.) the state name is now included in the sysfs interface 2.) detection, hotplug, and available state modifications are handled by CPUIDLE drivers directly 3.) the CPUIDLE idle handler is only ever installed when at least one cpuidle_device is enabled and ready 4.) the menu governor BM code no longer overflows 5.) the sysfs attributes are now printed as unsigned integers, avoiding negative values 6.) a variety of other small cleanups Also, Idle drivers are no longer swappable during runtime through the CPUIDLE sysfs inteface. On i386 and x86_64 most idle handlers (e.g. poll, mwait, halt, etc.) don't benefit from an infrastructure that supports multiple states, so I think using a more general case idle handler selection mechanism would be cleaner. Signed-off-by: Adam Belay <abelay@novell.com> Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Acked-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> commit df25b6b56955714e6e24b574d88d1fd11f0c3ee5 Author: Len Brown <len.brown@intel.com> Date: Tue Jul 24 17:08:21 2007 -0400 cpuidle: fix IA64 buid Signed-off-by: Len Brown <len.brown@intel.com> commit fd6ada4c14488755ff7068860078c437431fbccd Author: Adrian Bunk <bunk@stusta.de> Date: Mon Jul 9 11:33:13 2007 -0700 cpuidle: static make cpuidle_replace_governor() static Signed-off-by: Adrian Bunk <bunk@stusta.de> Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit c1d4a2cebcadf2429c0c72e1d29aa2a9684c32e0 Author: Adrian Bunk <bunk@stusta.de> Date: Tue Jul 3 00:54:40 2007 -0400 cpuidle: static This patch makes the needlessly global struct menu_governor static. Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit dbf8780c6e8d572c2c273da97ed1cca7608fd999 Author: Andrew Morton <akpm@linux-foundation.org> Date: Tue Jul 3 00:49:14 2007 -0400 export symbol tick_nohz_get_sleep_length ERROR: "tick_nohz_get_sleep_length" [drivers/cpuidle/governors/menu.ko] undefined! ERROR: "tick_nohz_get_idle_jiffies" [drivers/cpuidle/governors/menu.ko] undefined! And please be sure to get your changes to core kernel suitably reviewed. Cc: Adam Belay <abelay@novell.com> Cc: Venki Pallipadi <venkatesh.pallipadi@intel.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: john stultz <johnstul@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit 29f0e248e7017be15f99febf9143a2cef00b2961 Author: Andrew Morton <akpm@linux-foundation.org> Date: Tue Jul 3 00:43:04 2007 -0400 tick.h needs hrtimer.h It uses hrtimers. Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit e40cede7d63a029e92712a3fe02faee60cc38fb4 Author: Venki Pallipadi <venkatesh.pallipadi@intel.com> Date: Tue Jul 3 00:40:34 2007 -0400 cpuidle: first round of documentation updates Documentation changes based on Pavel's feedback. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit 83b42be2efece386976507555c29e7773a0dfcd1 Author: Venki Pallipadi <venkatesh.pallipadi@intel.com> Date: Tue Jul 3 00:39:25 2007 -0400 cpuidle: add rating to the governors and pick the one with highest rating by default Introduce a governor rating scheme to pick the right governor by default. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit d2a74b8c5e8f22def4709330d4bfc4a29209b71c Author: Venki Pallipadi <venkatesh.pallipadi@intel.com> Date: Tue Jul 3 00:38:08 2007 -0400 cpuidle: make cpuidle sysfs driver governor switch off by default Make default cpuidle sysfs to show current_governor and current_driver in read-only mode. More elaborate available_governors and available_drivers with writeable current_governor and current_driver interface only appear with "cpuidle_sysfs_switch" boot parameter. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit 1f60a0e80bf83cf6b55c8845bbe5596ed8f6307b Author: Venki Pallipadi <venkatesh.pallipadi@intel.com> Date: Tue Jul 3 00:37:00 2007 -0400 cpuidle: menu governor: change the early break condition Change the C-state early break out algorithm in menu governor. We only look at early breakouts that result in wakeups shorter than idle state's target_residency. If such a breakout is frequent enough, eliminate the particular idle state upto a timeout period. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit 45a42095cf64b003b4a69be3ce7f434f97d7af51 Author: Venki Pallipadi <venkatesh.pallipadi@intel.com> Date: Tue Jul 3 00:35:38 2007 -0400 cpuidle: fix uninitialized variable in sysfs routine Fix the uninitialized usage of ret. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit 80dca7cdba3e6ee13eae277660873ab9584eb3be Author: Venki Pallipadi <venkatesh.pallipadi@intel.com> Date: Tue Jul 3 00:34:16 2007 -0400 cpuidle: reenable /proc/acpi//power interface for the time being Keep /proc/acpi/processor/CPU*/power around for a while as powertop depends on it. It will be marked deprecated and removed in future. powertop can use cpuidle interfaces instead. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit 589c37c2646c5e3813a51255a5ee1159cb4c33fc Author: Venki Pallipadi <venkatesh.pallipadi@intel.com> Date: Tue Jul 3 00:32:37 2007 -0400 cpuidle: menu governor and hrtimer compile fix Compile fix for menu governor. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit 0ba80bd9ab3ed304cb4f19b722e4cc6740588b5e Author: Len Brown <len.brown@intel.com> Date: Thu May 31 22:51:43 2007 -0400 cpuidle: build fix - cpuidle vs ipw2100 module ERROR: "acpi_set_cstate_limit" [drivers/net/wireless/ipw2100.ko] undefined! Signed-off-by: Len Brown <len.brown@intel.com> commit d7d8fa7f96a7f7682be7c6cc0cc53fa7a18c3b58 Author: Adam Belay <abelay@novell.com> Date: Sat Mar 24 03:47:07 2007 -0400 cpuidle: add the 'menu' governor Here is my first take at implementing an idle PM governor that takes full advantage of NO_HZ. I call it the 'menu' governor because it considers the full list of idle states before each entry. I've kept the implementation fairly simple. It attempts to guess the next residency time and then chooses a state that would meet at least the break-even point between power savings and entry cost. To this end, it selects the deepest idle state that satisfies the following constraints: 1. If the idle time elapsed since bus master activity was detected is below a threshold (currently 20 ms), then limit the selection to C2-type or above. 2. Do not choose a state with a break-even residency that exceeds the expected time remaining until the next timer interrupt. 3. Do not choose a state with a break-even residency that exceeds the elapsed time between the last pair of break events, excluding timer interrupts. This governor has an advantage over "ladder" governor because it proactively checks how much time remains until the next timer interrupt using the tick infrastructure. Also, it handles device interrupt activity more intelligently by not including timer interrupts in break event calculations. Finally, it doesn't make policy decisions using the number of state entries, which can have variable residency times (NO_HZ makes these potentially very large), and instead only considers sleep time deltas. The menu governor can be selected during runtime using the cpuidle sysfs interface like so: "echo "menu" > /sys/devices/system/cpu/cpuidle/current_governor" Signed-off-by: Adam Belay <abelay@novell.com> Signed-off-by: Len Brown <len.brown@intel.com> commit a4bec7e65aa3b7488b879d971651cc99a6c410fe Author: Adam Belay <abelay@novell.com> Date: Sat Mar 24 03:47:03 2007 -0400 cpuidle: export time until next timer interrupt using NO_HZ Expose information about the time remaining until the next timer interrupt expires by utilizing the dynticks infrastructure. Also modify the main idle loop to allow dynticks to handle non-interrupt break events (e.g. DMA). Finally, expose sleep ticks information to external code. Thomas Gleixner is responsible for much of the code in this patch. However, I've made some additional changes, so I'm probably responsible if there are any bugs or oversights :) Signed-off-by: Adam Belay <abelay@novell.com> Signed-off-by: Len Brown <len.brown@intel.com> commit 2929d8996fbc77f41a5ff86bb67cdde3ca7d2d72 Author: Adam Belay <abelay@novell.com> Date: Sat Mar 24 03:46:58 2007 -0400 cpuidle: governor API changes This patch prepares cpuidle for the menu governor. It adds an optional stage after idle state entry to give the governor an opportunity to check why the state was exited. Also it makes sure the idle loop returns after each state entry, allowing the appropriate dynticks code to run. Signed-off-by: Adam Belay <abelay@novell.com> Signed-off-by: Len Brown <len.brown@intel.com> commit 3a7fd42f9825c3b03e364ca59baa751bb350775f Author: Venki Pallipadi <venkatesh.pallipadi@intel.com> Date: Thu Apr 26 00:03:59 2007 -0700 cpuidle: hang fix Prevent hang on x86-64, when ACPI processor driver is added as a module on a system that does not support C-states. x86-64 expects all idle handlers to enable interrupts before returning from idle handler. This is due to enter_idle(), exit_idle() races. Make cpuidle_idle_call() confirm to this when there is no pm_idle_old. Also, cpuidle look at the return values of attch_driver() and set current_driver to NULL if attach fails on all CPUs. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit 4893339a142afbd5b7c01ffadfd53d14746e858e Author: Shaohua Li <shaohua.li@intel.com> Date: Thu Apr 26 10:40:09 2007 +0800 cpuidle: add support for max_cstate limit With CPUIDLE framework, the max_cstate (to limit max cpu c-state) parameter is ingored. Some systems require it to ignore C2/C3 and some drivers like ipw require it too. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> commit 43bbbbe1cb998cbd2df656f55bb3bfe30f30e7d1 Author: Shaohua Li <shaohua.li@intel.com> Date: Thu Apr 26 10:40:13 2007 +0800 cpuidle: add cpuidle_fore_redetect_devices API add cpuidle_force_redetect_devices API, which forces all CPU redetect idle states. Next patch will use it. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> commit d1edadd608f24836def5ec483d2edccfb37b1d19 Author: Shaohua Li <shaohua.li@intel.com> Date: Thu Apr 26 10:40:01 2007 +0800 cpuidle: fix sysfs related issue Fix the cpuidle sysfs issue. a. make kobject dynamicaly allocated b. fixed sysfs init issue to avoid suspend/resume issue Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> commit 7169a5cc0d67b263978859672e86c13c23a5570d Author: Randy Dunlap <randy.dunlap@oracle.com> Date: Wed Mar 28 22:52:53 2007 -0400 cpuidle: 1-bit field must be unsigned A 1-bit bitfield has no room for a sign bit. drivers/cpuidle/governors/ladder.c:54:16: error: dubious bitfield without explicit `signed' or `unsigned' Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit 4658620158dc2fbd9e4bcb213c5b6fb5d05ba7d4 Author: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Date: Wed Mar 28 22:52:41 2007 -0400 cpuidle: fix boot hang Patch for cpuidle boot hang reported by Larry Finger here. http://www.ussg.iu.edu/hypermail/linux/kernel/0703.2/2025.html Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Cc: Larry Finger <larry.finger@lwfinger.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit c17e168aa6e5fe3851baaae8df2fbc1cf11443a9 Author: Len Brown <len.brown@intel.com> Date: Wed Mar 7 04:37:53 2007 -0500 cpuidle: ladder does not depend on ACPI build fix for CONFIG_ACPI=n In file included from drivers/cpuidle/governors/ladder.c:21: include/acpi/processor.h:88: error: expected specifier-qualifier-list before ‘acpi_integer’ include/acpi/processor.h:106: error: expected specifier-qualifier-list before ‘acpi_integer’ include/acpi/processor.h:168: error: expected specifier-qualifier-list before ‘acpi_handle’ Signed-off-by: Len Brown <len.brown@intel.com> commit 8c91d958246bde68db0c3f0c57b535962ce861cb Author: Adrian Bunk <bunk@stusta.de> Date: Tue Mar 6 02:29:40 2007 -0800 cpuidle: make code static This patch makes the following needlessly global code static: - driver.c: __cpuidle_find_driver() - governor.c: __cpuidle_find_governor() - ladder.c: struct ladder_governor Signed-off-by: Adrian Bunk <bunk@stusta.de> Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Cc: Adam Belay <abelay@novell.com> Cc: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit 0c39dc3187094c72c33ab65a64d2017b21f372d2 Author: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Date: Wed Mar 7 02:38:22 2007 -0500 cpu_idle: fix build break This patch fixes a build breakage with !CONFIG_HOTPLUG_CPU and CONFIG_CPU_IDLE. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit 8112e3b115659b07df340ef170515799c0105f82 Author: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Date: Tue Mar 6 02:29:39 2007 -0800 cpuidle: build fix for !CPU_IDLE Fix the compile issues when CPU_IDLE is not configured. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Cc: Adam Belay <abelay@novell.com> Cc: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com> commit 1eb4431e9599cd25e0d9872f3c2c8986821839dd Author: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Date: Thu Feb 22 13:54:57 2007 -0800 cpuidle take2: Basic documentation for cpuidle Documentation for cpuidle infrastructure Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Adam Belay <abelay@novell.com> Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> commit ef5f15a8b79123a047285ec2e3899108661df779 Author: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Date: Thu Feb 22 13:54:03 2007 -0800 cpuidle take2: Hookup ACPI C-states driver with cpuidle Hookup ACPI C-states onto generic cpuidle infrastructure. drivers/acpi/procesor_idle.c is now a ACPI C-states driver that registers as a driver in cpuidle infrastructure and the policy part is removed from drivers/acpi/processor_idle.c. We use governor in cpuidle instead. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Adam Belay <abelay@novell.com> Signed-off-by: Len Brown <len.brown@intel.com> commit 987196fa82d4db52c407e8c9d5dec884ba602183 Author: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Date: Thu Feb 22 13:52:57 2007 -0800 cpuidle take2: Core cpuidle infrastructure Announcing 'cpuidle', a new CPU power management infrastructure to manage idle CPUs in a clean and efficient manner. cpuidle separates out the drivers that can provide support for multiple types of idle states and policy governors that decide on what idle state to use at run time. A cpuidle driver can support multiple idle states based on parameters like varying power consumption, wakeup latency, etc (ACPI C-states for example). A cpuidle governor can be usage model specific (laptop, server, laptop on battery etc). Main advantage of the infrastructure being, it allows independent development of drivers and governors and allows for better CPU power management. A huge thanks to Adam Belay and Shaohua Li who were part of this mini-project since its beginning and are greatly responsible for this patchset. This patch: Core cpuidle infrastructure. Introduces a new abstraction layer for cpuidle: * which manages drivers that can support multiple idles states. Drivers can be generic or particular to specific hardware/platform * allows pluging in multiple policy governors that can take idle state policy decision * The core also has a set of sysfs interfaces with which administrato can know about supported drivers and governors and switch them at run time. Signed-off-by: Adam Belay <abelay@novell.com> Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> Signed-off-by: Len Brown <len.brown@intel.com>
2007-10-03 22:58:00 +00:00
/**
* tick_nohz_get_sleep_length - return the length of the current sleep
*
* Called from power state control code with interrupts disabled
*/
ktime_t tick_nohz_get_sleep_length(void)
{
struct tick_sched *ts = &__get_cpu_var(tick_cpu_sched);
return ts->sleep_length;
}
static void tick_nohz_restart(struct tick_sched *ts, ktime_t now)
{
hrtimer_cancel(&ts->sched_timer);
hrtimer_set_expires(&ts->sched_timer, ts->idle_tick);
while (1) {
/* Forward the time to expire in the future */
hrtimer_forward(&ts->sched_timer, now, tick_period);
if (ts->nohz_mode == NOHZ_MODE_HIGHRES) {
hrtimer_start_expires(&ts->sched_timer,
HRTIMER_MODE_ABS_PINNED);
/* Check, if the timer was already in the past */
if (hrtimer_active(&ts->sched_timer))
break;
} else {
if (!tick_program_event(
hrtimer_get_expires(&ts->sched_timer), 0))
break;
}
/* Reread time and update jiffies */
now = ktime_get();
tick_do_update_jiffies64(now);
}
}
static void tick_nohz_restart_sched_tick(struct tick_sched *ts, ktime_t now)
{
/* Update jiffies first */
select_nohz_load_balancer(0);
tick_do_update_jiffies64(now);
update_cpu_load_nohz();
nohz: Make nohz API agnostic against idle ticks cputime accounting When the timer tick fires, it accounts the new jiffy as either part of system, user or idle time. This is how we record the cputime statistics. But when the tick is stopped from the idle task, we still need to record the number of jiffies spent tickless until we restart the tick and fall back to traditional tick-based cputime accounting. To do this, we take a snapshot of jiffies when the tick is stopped and compute the difference against the new value of jiffies when the tick is restarted. Then we account this whole difference to the idle cputime. However we are preparing to be able to stop the tick from other places than idle. So this idle time accounting needs to be performed from the callers of nohz APIs, not from the nohz APIs themselves because we now want them to be agnostic against places that stop/restart tick. Therefore, we pull the tickless idle time accounting out of generic nohz helpers up to idle entry/exit callers. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Alessio Igor Bogani <abogani@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Avi Kivity <avi@redhat.com> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Christoph Lameter <cl@linux.com> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Geoff Levand <geoff@infradead.org> Cc: Gilad Ben Yossef <gilad@benyossef.com> Cc: Hakan Akkan <hakanakkan@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Kevin Hilman <khilman@ti.com> Cc: Max Krasnyansky <maxk@qualcomm.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephen Hemminger <shemminger@vyatta.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Sven-Thorsten Dietrich <thebigcorporation@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de>
2011-07-28 02:00:47 +00:00
touch_softlockup_watchdog();
/*
* Cancel the scheduled timer and restore the tick
*/
ts->tick_stopped = 0;
ts->idle_exittime = now;
tick_nohz_restart(ts, now);
}
static void tick_nohz_account_idle_ticks(struct tick_sched *ts)
{
2008-12-31 14:11:38 +00:00
#ifndef CONFIG_VIRT_CPU_ACCOUNTING
nohz: Make nohz API agnostic against idle ticks cputime accounting When the timer tick fires, it accounts the new jiffy as either part of system, user or idle time. This is how we record the cputime statistics. But when the tick is stopped from the idle task, we still need to record the number of jiffies spent tickless until we restart the tick and fall back to traditional tick-based cputime accounting. To do this, we take a snapshot of jiffies when the tick is stopped and compute the difference against the new value of jiffies when the tick is restarted. Then we account this whole difference to the idle cputime. However we are preparing to be able to stop the tick from other places than idle. So this idle time accounting needs to be performed from the callers of nohz APIs, not from the nohz APIs themselves because we now want them to be agnostic against places that stop/restart tick. Therefore, we pull the tickless idle time accounting out of generic nohz helpers up to idle entry/exit callers. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Alessio Igor Bogani <abogani@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Avi Kivity <avi@redhat.com> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Christoph Lameter <cl@linux.com> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Geoff Levand <geoff@infradead.org> Cc: Gilad Ben Yossef <gilad@benyossef.com> Cc: Hakan Akkan <hakanakkan@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Kevin Hilman <khilman@ti.com> Cc: Max Krasnyansky <maxk@qualcomm.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephen Hemminger <shemminger@vyatta.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Sven-Thorsten Dietrich <thebigcorporation@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de>
2011-07-28 02:00:47 +00:00
unsigned long ticks;
/*
* We stopped the tick in idle. Update process times would miss the
* time we slept as update_process_times does only a 1 tick
* accounting. Enforce that this is accounted to idle !
*/
ticks = jiffies - ts->idle_jiffies;
/*
* We might be one off. Do not randomly account a huge number of ticks!
*/
2008-12-31 14:11:38 +00:00
if (ticks && ticks < LONG_MAX)
account_idle_ticks(ticks);
#endif
}
/**
* tick_nohz_idle_exit - restart the idle tick from the idle task
*
* Restart the idle tick when the CPU is woken up from idle
* This also exit the RCU extended quiescent state. The CPU
* can use RCU again after this function is called.
*/
void tick_nohz_idle_exit(void)
{
int cpu = smp_processor_id();
struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
ktime_t now;
local_irq_disable();
WARN_ON_ONCE(!ts->inidle);
ts->inidle = 0;
if (ts->idle_active || ts->tick_stopped)
now = ktime_get();
if (ts->idle_active)
tick_nohz_stop_idle(cpu, now);
nohz: Make nohz API agnostic against idle ticks cputime accounting When the timer tick fires, it accounts the new jiffy as either part of system, user or idle time. This is how we record the cputime statistics. But when the tick is stopped from the idle task, we still need to record the number of jiffies spent tickless until we restart the tick and fall back to traditional tick-based cputime accounting. To do this, we take a snapshot of jiffies when the tick is stopped and compute the difference against the new value of jiffies when the tick is restarted. Then we account this whole difference to the idle cputime. However we are preparing to be able to stop the tick from other places than idle. So this idle time accounting needs to be performed from the callers of nohz APIs, not from the nohz APIs themselves because we now want them to be agnostic against places that stop/restart tick. Therefore, we pull the tickless idle time accounting out of generic nohz helpers up to idle entry/exit callers. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Alessio Igor Bogani <abogani@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Avi Kivity <avi@redhat.com> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Christoph Lameter <cl@linux.com> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Geoff Levand <geoff@infradead.org> Cc: Gilad Ben Yossef <gilad@benyossef.com> Cc: Hakan Akkan <hakanakkan@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Kevin Hilman <khilman@ti.com> Cc: Max Krasnyansky <maxk@qualcomm.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephen Hemminger <shemminger@vyatta.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Sven-Thorsten Dietrich <thebigcorporation@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de>
2011-07-28 02:00:47 +00:00
if (ts->tick_stopped) {
tick_nohz_restart_sched_tick(ts, now);
nohz: Make nohz API agnostic against idle ticks cputime accounting When the timer tick fires, it accounts the new jiffy as either part of system, user or idle time. This is how we record the cputime statistics. But when the tick is stopped from the idle task, we still need to record the number of jiffies spent tickless until we restart the tick and fall back to traditional tick-based cputime accounting. To do this, we take a snapshot of jiffies when the tick is stopped and compute the difference against the new value of jiffies when the tick is restarted. Then we account this whole difference to the idle cputime. However we are preparing to be able to stop the tick from other places than idle. So this idle time accounting needs to be performed from the callers of nohz APIs, not from the nohz APIs themselves because we now want them to be agnostic against places that stop/restart tick. Therefore, we pull the tickless idle time accounting out of generic nohz helpers up to idle entry/exit callers. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Alessio Igor Bogani <abogani@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Avi Kivity <avi@redhat.com> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Christoph Lameter <cl@linux.com> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Geoff Levand <geoff@infradead.org> Cc: Gilad Ben Yossef <gilad@benyossef.com> Cc: Hakan Akkan <hakanakkan@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Kevin Hilman <khilman@ti.com> Cc: Max Krasnyansky <maxk@qualcomm.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephen Hemminger <shemminger@vyatta.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Sven-Thorsten Dietrich <thebigcorporation@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de>
2011-07-28 02:00:47 +00:00
tick_nohz_account_idle_ticks(ts);
}
local_irq_enable();
}
static int tick_nohz_reprogram(struct tick_sched *ts, ktime_t now)
{
hrtimer_forward(&ts->sched_timer, now, tick_period);
return tick_program_event(hrtimer_get_expires(&ts->sched_timer), 0);
}
/*
* The nohz low res interrupt handler
*/
static void tick_nohz_handler(struct clock_event_device *dev)
{
struct tick_sched *ts = &__get_cpu_var(tick_cpu_sched);
struct pt_regs *regs = get_irq_regs();
int cpu = smp_processor_id();
ktime_t now = ktime_get();
dev->next_event.tv64 = KTIME_MAX;
/*
* Check if the do_timer duty was dropped. We don't care about
* concurrency: This happens only when the cpu in charge went
* into a long sleep. If two cpus happen to assign themself to
* this duty, then the jiffies update is still serialized by
* xtime_lock.
*/
if (unlikely(tick_do_timer_cpu == TICK_DO_TIMER_NONE))
tick_do_timer_cpu = cpu;
/* Check, if the jiffies need an update */
if (tick_do_timer_cpu == cpu)
tick_do_update_jiffies64(now);
/*
* When we are idle and the tick is stopped, we have to touch
* the watchdog as we might not schedule for a really long
* time. This happens on complete idle SMP systems while
* waiting on the login prompt. We also increment the "start
* of idle" jiffy stamp so the idle accounting adjustment we
* do when we go busy again does not account too much ticks.
*/
if (ts->tick_stopped) {
touch_softlockup_watchdog();
ts->idle_jiffies++;
}
update_process_times(user_mode(regs));
profile_tick(CPU_PROFILING);
while (tick_nohz_reprogram(ts, now)) {
now = ktime_get();
tick_do_update_jiffies64(now);
}
}
/**
* tick_nohz_switch_to_nohz - switch to nohz mode
*/
static void tick_nohz_switch_to_nohz(void)
{
struct tick_sched *ts = &__get_cpu_var(tick_cpu_sched);
ktime_t next;
if (!tick_nohz_enabled)
return;
local_irq_disable();
if (tick_switch_to_oneshot(tick_nohz_handler)) {
local_irq_enable();
return;
}
ts->nohz_mode = NOHZ_MODE_LOWRES;
/*
* Recycle the hrtimer in ts, so we can share the
* hrtimer_forward with the highres code.
*/
hrtimer_init(&ts->sched_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
/* Get the next period */
next = tick_init_jiffy_update();
for (;;) {
hrtimer_set_expires(&ts->sched_timer, next);
if (!tick_program_event(next, 0))
break;
next = ktime_add(next, tick_period);
}
local_irq_enable();
}
/*
* When NOHZ is enabled and the tick is stopped, we need to kick the
* tick timer from irq_enter() so that the jiffies update is kept
* alive during long running softirqs. That's ugly as hell, but
* correctness is key even if we need to fix the offending softirq in
* the first place.
*
* Note, this is different to tick_nohz_restart. We just kick the
* timer and do not touch the other magic bits which need to be done
* when idle is left.
*/
static void tick_nohz_kick_tick(int cpu, ktime_t now)
{
#if 0
/* Switch back to 2.6.27 behaviour */
struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
ktime_t delta;
/*
* Do not touch the tick device, when the next expiry is either
* already reached or less/equal than the tick period.
*/
delta = ktime_sub(hrtimer_get_expires(&ts->sched_timer), now);
if (delta.tv64 <= tick_period.tv64)
return;
tick_nohz_restart(ts, now);
#endif
}
static inline void tick_check_nohz(int cpu)
{
struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
ktime_t now;
if (!ts->idle_active && !ts->tick_stopped)
return;
now = ktime_get();
if (ts->idle_active)
tick_nohz_stop_idle(cpu, now);
if (ts->tick_stopped) {
tick_nohz_update_jiffies(now);
tick_nohz_kick_tick(cpu, now);
}
}
#else
static inline void tick_nohz_switch_to_nohz(void) { }
static inline void tick_check_nohz(int cpu) { }
#endif /* NO_HZ */
/*
* Called from irq_enter to notify about the possible interruption of idle()
*/
void tick_check_idle(int cpu)
{
tick_check_oneshot_broadcast(cpu);
tick_check_nohz(cpu);
}
/*
* High resolution timer specific code
*/
#ifdef CONFIG_HIGH_RES_TIMERS
/*
* We rearm the timer until we get disabled by the idle code.
* Called with interrupts disabled and timer->base->cpu_base->lock held.
*/
static enum hrtimer_restart tick_sched_timer(struct hrtimer *timer)
{
struct tick_sched *ts =
container_of(timer, struct tick_sched, sched_timer);
struct pt_regs *regs = get_irq_regs();
ktime_t now = ktime_get();
int cpu = smp_processor_id();
#ifdef CONFIG_NO_HZ
/*
* Check if the do_timer duty was dropped. We don't care about
* concurrency: This happens only when the cpu in charge went
* into a long sleep. If two cpus happen to assign themself to
* this duty, then the jiffies update is still serialized by
* xtime_lock.
*/
if (unlikely(tick_do_timer_cpu == TICK_DO_TIMER_NONE))
tick_do_timer_cpu = cpu;
#endif
/* Check, if the jiffies need an update */
if (tick_do_timer_cpu == cpu)
tick_do_update_jiffies64(now);
/*
* Do not call, when we are not in irq context and have
* no valid regs pointer
*/
if (regs) {
/*
* When we are idle and the tick is stopped, we have to touch
* the watchdog as we might not schedule for a really long
* time. This happens on complete idle SMP systems while
* waiting on the login prompt. We also increment the "start of
* idle" jiffy stamp so the idle accounting adjustment we do
* when we go busy again does not account too much ticks.
*/
if (ts->tick_stopped) {
touch_softlockup_watchdog();
nohz: Make nohz API agnostic against idle ticks cputime accounting When the timer tick fires, it accounts the new jiffy as either part of system, user or idle time. This is how we record the cputime statistics. But when the tick is stopped from the idle task, we still need to record the number of jiffies spent tickless until we restart the tick and fall back to traditional tick-based cputime accounting. To do this, we take a snapshot of jiffies when the tick is stopped and compute the difference against the new value of jiffies when the tick is restarted. Then we account this whole difference to the idle cputime. However we are preparing to be able to stop the tick from other places than idle. So this idle time accounting needs to be performed from the callers of nohz APIs, not from the nohz APIs themselves because we now want them to be agnostic against places that stop/restart tick. Therefore, we pull the tickless idle time accounting out of generic nohz helpers up to idle entry/exit callers. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Alessio Igor Bogani <abogani@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Avi Kivity <avi@redhat.com> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Christoph Lameter <cl@linux.com> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Geoff Levand <geoff@infradead.org> Cc: Gilad Ben Yossef <gilad@benyossef.com> Cc: Hakan Akkan <hakanakkan@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Kevin Hilman <khilman@ti.com> Cc: Max Krasnyansky <maxk@qualcomm.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephen Hemminger <shemminger@vyatta.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Sven-Thorsten Dietrich <thebigcorporation@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de>
2011-07-28 02:00:47 +00:00
if (idle_cpu(cpu))
ts->idle_jiffies++;
}
update_process_times(user_mode(regs));
profile_tick(CPU_PROFILING);
}
hrtimer_forward(timer, now, tick_period);
return HRTIMER_RESTART;
}
static int sched_skew_tick;
static int __init skew_tick(char *str)
{
get_option(&str, &sched_skew_tick);
return 0;
}
early_param("skew_tick", skew_tick);
/**
* tick_setup_sched_timer - setup the tick emulation timer
*/
void tick_setup_sched_timer(void)
{
struct tick_sched *ts = &__get_cpu_var(tick_cpu_sched);
ktime_t now = ktime_get();
/*
* Emulate tick processing via per-CPU hrtimers:
*/
hrtimer_init(&ts->sched_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
ts->sched_timer.function = tick_sched_timer;
/* Get the next period (per cpu) */
hrtimer_set_expires(&ts->sched_timer, tick_init_jiffy_update());
/* Offset the tick to avert xtime_lock contention. */
if (sched_skew_tick) {
u64 offset = ktime_to_ns(tick_period) >> 1;
do_div(offset, num_possible_cpus());
offset *= smp_processor_id();
hrtimer_add_expires_ns(&ts->sched_timer, offset);
}
for (;;) {
hrtimer_forward(&ts->sched_timer, now, tick_period);
hrtimer_start_expires(&ts->sched_timer,
HRTIMER_MODE_ABS_PINNED);
/* Check, if the timer was already in the past */
if (hrtimer_active(&ts->sched_timer))
break;
now = ktime_get();
}
#ifdef CONFIG_NO_HZ
if (tick_nohz_enabled)
ts->nohz_mode = NOHZ_MODE_HIGHRES;
#endif
}
#endif /* HIGH_RES_TIMERS */
#if defined CONFIG_NO_HZ || defined CONFIG_HIGH_RES_TIMERS
void tick_cancel_sched_timer(int cpu)
{
struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
# ifdef CONFIG_HIGH_RES_TIMERS
if (ts->sched_timer.base)
hrtimer_cancel(&ts->sched_timer);
# endif
ts->nohz_mode = NOHZ_MODE_INACTIVE;
}
#endif
/**
* Async notification about clocksource changes
*/
void tick_clock_notify(void)
{
int cpu;
for_each_possible_cpu(cpu)
set_bit(0, &per_cpu(tick_cpu_sched, cpu).check_clocks);
}
/*
* Async notification about clock event changes
*/
void tick_oneshot_notify(void)
{
struct tick_sched *ts = &__get_cpu_var(tick_cpu_sched);
set_bit(0, &ts->check_clocks);
}
/**
* Check, if a change happened, which makes oneshot possible.
*
* Called cyclic from the hrtimer softirq (driven by the timer
* softirq) allow_nohz signals, that we can switch into low-res nohz
* mode, because high resolution timers are disabled (either compile
* or runtime).
*/
int tick_check_oneshot_change(int allow_nohz)
{
struct tick_sched *ts = &__get_cpu_var(tick_cpu_sched);
if (!test_and_clear_bit(0, &ts->check_clocks))
return 0;
if (ts->nohz_mode != NOHZ_MODE_INACTIVE)
return 0;
if (!timekeeping_valid_for_hres() || !tick_is_oneshot_available())
return 0;
if (!allow_nohz)
return 1;
tick_nohz_switch_to_nohz();
return 0;
}