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John Stultz 2d42244ae7 clocksource: introduce CLOCK_MONOTONIC_RAW 
In talking with Josip Loncaric, and his work on clock synchronization (see
btime.sf.net), he mentioned that for really close synchronization, it is
useful to have access to "hardware time", that is a notion of time that is
not in any way adjusted by the clock slewing done to keep close time sync.

Part of the issue is if we are using the kernel's ntp adjusted
representation of time in order to measure how we should correct time, we
can run into what Paul McKenney aptly described as "Painting a road using
the lines we're painting as the guide".

I had been thinking of a similar problem, and was trying to come up with a
way to give users access to a purely hardware based time representation
that avoided users having to know the underlying frequency and mask values
needed to deal with the wide variety of possible underlying hardware
counters.

My solution is to introduce CLOCK_MONOTONIC_RAW.  This exposes a
nanosecond based time value, that increments starting at bootup and has no
frequency adjustments made to it what so ever.

The time is accessed from userspace via the posix_clock_gettime() syscall,
passing CLOCK_MONOTONIC_RAW as the clock_id.

Signed-off-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-21 09:50:24 +02:00
..
irq genirq: switch /proc/irq/*/smp_affinity et al to seqfiles 2008-08-12 16:07:30 -07:00
power kexec jump: save/restore device state 2008-07-26 12:00:04 -07:00
time clocksource: introduce CLOCK_MONOTONIC_RAW 2008-08-21 09:50:24 +02:00
trace Merge branch 'linus' into cpus4096 2008-07-28 23:32:00 +02:00
.gitignore Update kernel/.gitignore with new auto-generated files 2008-02-09 23:27:01 -08:00
acct.c bsdacct: fix and add comments around acct_process() 2008-07-25 10:53:47 -07:00
audit.c [PATCH] Fix the bug of using AUDIT_STATUS_RATE_LIMIT when set fail, no error output. 2008-08-01 12:15:16 -04:00
audit.h [PATCH 1/2] audit: move extern declarations to audit.h 2008-04-28 06:28:04 -04:00
audit_tree.c [PATCH] list_for_each_rcu must die: audit 2008-05-17 03:30:23 -04:00
auditfilter.c Re: [PATCH] the loginuid field should be output in all AUDIT_CONFIG_CHANGE audit messages 2008-08-01 12:15:03 -04:00
auditsc.c Re: [PATCH] Fix the kernel panic of audit_filter_task when key field is set 2008-08-04 06:13:50 -04:00
backtracetest.c backtrace: replace timer with tasklet + completions 2008-06-27 18:09:16 +02:00
bounds.c Add kbuild.h that contains common definitions for kbuild users 2008-04-29 08:06:29 -07:00
capability.c security: Fix setting of PF_SUPERPRIV by __capable() 2008-08-14 22:59:43 +10:00
cgroup.c cgroup: uninline cgroup_has_css_refs() 2008-07-30 09:41:44 -07:00
cgroup_debug.c CGroup API files: move "releasable" to cgroup_debug subsystem 2008-04-29 08:06:09 -07:00
compat.c ntp: support for TAI 2008-05-01 08:03:59 -07:00
configs.c kernel: use non-racy method for proc entries creation 2008-04-29 08:06:22 -07:00
cpu.c cpu hotplug: s390 doesn't support additional_cpus anymore. 2008-08-12 16:07:28 -07:00
cpuset.c cpuset: clean up cpuset hierarchy traversal code 2008-07-30 09:41:44 -07:00
delayacct.c per-task-delay-accounting: update taskstats for memory reclaim delay 2008-07-25 10:53:47 -07:00
dma-coherent.c DMA: make dma-coherent.c documentation kdoc-friendly 2008-08-07 06:52:01 -07:00
dma.c kernel: use non-racy method for proc entries creation 2008-04-29 08:06:22 -07:00
exec_domain.c [PATCH] kill altroot 2008-07-26 20:53:20 -04:00
exit.c tracehook: fix exit_signal=0 case 2008-08-01 12:01:11 -07:00
extable.c module: Don't report discarded init pages as kernel text. 2008-01-29 17:13:18 +11:00
fork.c mmu-notifiers: core 2008-07-28 16:30:21 -07:00
futex.c futexes: fix fault handling in futex_lock_pi 2008-06-23 13:31:15 +02:00
futex_compat.c futex_compat __user annotation 2008-03-30 14:18:41 -07:00
hrtimer.c Merge branch 'generic-ipi' into generic-ipi-for-linus 2008-07-15 21:55:59 +02:00
itimer.c ITIMER_REAL: convert to use struct pid 2008-02-08 09:22:29 -08:00
kallsyms.c kallsyms: fix potential overflow in binary search 2008-07-25 10:53:27 -07:00
Kconfig.hz sched: fix SCHED_HRTICK dependency 2008-07-28 14:37:38 +02:00
Kconfig.preempt rcu: move PREEMPT_RCU config option back under PREEMPT 2008-03-10 18:01:20 -07:00
kexec.c kexec: use a mutex for locking rather than xchg() 2008-08-15 08:35:43 -07:00
kfifo.c
kgdb.c kgdb: fix gdb serial thread queries 2008-08-01 08:39:35 -05:00
kmod.c call_usermodehelper(): increase reliability 2008-07-25 10:53:28 -07:00
kprobes.c kprobes: remove redundant config check 2008-07-25 10:53:30 -07:00
ksysfs.c Kobject: convert remaining kobject_unregister() to kobject_put() 2008-01-24 20:40:40 -08:00
kthread.c tracehook: wait_task_inactive 2008-07-26 12:00:09 -07:00
latencytop.c kernel: use non-racy method for proc entries creation 2008-04-29 08:06:22 -07:00
lockdep.c lockdep: fix spurious 'inconsistent lock state' warning 2008-08-18 09:42:31 +02:00
lockdep_internals.h lockdep: build fix 2008-08-13 12:55:10 +02:00
lockdep_proc.c lockdep: fix build if CONFIG_PROVE_LOCKING not defined 2008-08-15 19:22:04 +02:00
Makefile Merge branch 'linus' into core/generic-dma-coherent 2008-07-29 00:07:55 +02:00
marker.c markers: fix markers read barrier for multiple probes 2008-07-30 09:41:45 -07:00
module.c modules: extend initcall_debug functionality to the module loader 2008-08-12 17:52:54 +10:00
mutex-debug.c mutex-debug: check mutex magic before owner 2008-05-16 16:53:35 +02:00
mutex-debug.h
mutex.c locking: fix mutex @key parameter kernel-doc notation 2008-07-28 18:12:36 +02:00
mutex.h
notifier.c ipc: re-enable msgmni automatic recomputing msgmni if set to negative 2008-04-29 08:06:13 -07:00
ns_cgroup.c cgroup_clone: use pid of newly created task for new cgroup 2008-07-25 10:53:37 -07:00
nsproxy.c cgroup_clone: use pid of newly created task for new cgroup 2008-07-25 10:53:37 -07:00
panic.c Add a WARN() macro; this is WARN_ON() + printk arguments 2008-07-25 10:53:29 -07:00
params.c Add new string functions strict_strto* and convert kernel params to use them 2008-02-08 09:22:41 -08:00
pid.c pidns: remove now unused find_pid function. 2008-07-25 10:53:45 -07:00
pid_namespace.c bsdacct: switch from global bsd_acct_struct instance to per-pidns one 2008-07-25 10:53:47 -07:00
pm_qos_params.c pm_qos: spelling fixes 2008-08-05 14:33:50 -07:00
posix-cpu-timers.c posix-timers: print RT watchdog message 2008-05-24 18:49:22 +02:00
posix-timers.c clocksource: introduce CLOCK_MONOTONIC_RAW 2008-08-21 09:50:24 +02:00
printk.c printk: fix comment for printk ratelimiting 2008-07-30 09:41:45 -07:00
profile.c build kernel/profile.o only when requested 2008-07-25 10:53:27 -07:00
ptrace.c security: Fix setting of PF_SUPERPRIV by __capable() 2008-08-14 22:59:43 +10:00
rcuclassic.c stop_machine: Wean existing callers off stop_machine_run() 2008-07-28 12:16:31 +10:00
rcupdate.c Merge branch 'generic-ipi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2008-07-15 14:12:03 -07:00
rcupreempt.c Merge branch 'linus' into cpus4096 2008-07-16 00:29:07 +02:00
rcupreempt_trace.c rcu: remove duplicated include in kernel/rcupreempt_trace.c 2008-05-19 10:03:39 +02:00
rcutorture.c rcu: make rcutorture even more vicious: invoke RCU readers from irq handlers (timers) 2008-06-26 09:24:33 +02:00
relay.c relay: fix "full buffer with exactly full last subbuffer" accounting problem 2008-08-05 14:33:46 -07:00
res_counter.c cgroup files: convert res_counter_write() to be a cgroups write_string() handler 2008-07-25 10:53:36 -07:00
resource.c resource: add resource_size() 2008-07-30 09:41:43 -07:00
rtmutex-debug.c Don't operate with pid_t in rtmutex tester 2008-02-08 09:22:41 -08:00
rtmutex-debug.h
rtmutex-tester.c sysdev: Pass the attribute to the low level sysdev show/store function 2008-07-21 21:55:02 -07:00
rtmutex.c hrtimer: more hrtimer_init_sleeper() fallout. 2008-02-13 15:45:36 +01:00
rtmutex.h
rtmutex_common.h Don't operate with pid_t in rtmutex tester 2008-02-08 09:22:41 -08:00
rwsem.c sched: mark rwsem functions as __sched for wchan/profiling 2007-12-18 15:21:13 +01:00
sched.c Merge branch 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2008-08-16 17:15:32 -07:00
sched_clock.c sched_clock: delay using sched_clock() 2008-08-11 08:59:03 +02:00
sched_cpupri.c sched: use a 2-d bitmap for searching lowest-pri CPU 2008-06-06 15:19:28 +02:00
sched_cpupri.h sched: fix the cpuprio count really 2008-06-06 15:19:44 +02:00
sched_debug.c sched: add full schedstats to /proc/sched_debug 2008-06-27 14:31:31 +02:00
sched_fair.c sched: fix mysql+oltp regression 2008-08-11 14:49:29 +02:00
sched_features.h sched: bias effective_load() error towards failing wake_affine(). 2008-06-27 14:31:47 +02:00
sched_idletask.c sched: make rt_sched_class, idle_sched_class static 2008-05-05 23:56:17 +02:00
sched_rt.c sched: fix rt-bandwidth hotplug race 2008-08-14 15:50:58 +02:00
sched_stats.h sched: fix accounting in task delay accounting & migration 2008-07-04 12:50:23 +02:00
seccomp.c
semaphore.c semaphore: __down_common: use signal_pending_state() 2008-08-05 14:33:47 -07:00
signal.c tracehook: fix SA_NOCLDWAIT 2008-08-19 20:37:07 -07:00
smp.c generic-ipi: fix stack and rcu interaction bug in smp_call_function_mask(), fix 2008-08-12 11:21:27 +02:00
softirq.c Full conversion to early_initcall() interface, remove old interface 2008-07-26 12:00:04 -07:00
softlockup.c Full conversion to early_initcall() interface, remove old interface 2008-07-26 12:00:04 -07:00
spinlock.c lockdep: spin_lock_nest_lock(), checkpatch fixes 2008-08-13 13:56:51 +02:00
srcu.c make srcu_readers_active() static 2008-02-06 10:41:02 -08:00
stacktrace.c stacktrace: fix modular build, export print_stack_trace and save_stack_trace 2008-06-30 09:20:55 +02:00
stop_machine.c stop_machine: remove unused variable 2008-08-12 17:52:55 +10:00
sys.c fix setpriority(PRIO_PGRP) thread iterator breakage 2008-08-20 15:40:32 -07:00
sys_ni.c signalfd: fix undefined reference to `compat_sys_signalfd4' when !CONFIG_SIGNALFD 2008-07-25 11:35:41 -07:00
sysctl.c lost sysctl fix 2008-07-27 09:45:34 -07:00
sysctl_check.c sysctl: check for bogus modes 2008-07-25 10:53:45 -07:00
taskstats.c taskstats: remove initialization of static per-cpu variable 2008-07-25 10:53:47 -07:00
test_kprobes.c kprobes: kretprobe user entry-handler 2008-02-06 10:41:11 -08:00
time.c Make constants in kernel/timeconst.h fixed 64 bits 2008-05-02 16:18:42 -07:00
timeconst.pl Make constants in kernel/timeconst.h fixed 64 bits 2008-05-02 16:18:42 -07:00
timer.c Merge branch 'for-linus' of master.kernel.org:/home/rmk/linux-2.6-arm 2008-07-14 16:06:58 -07:00
tsacct.c task IO accounting: move all IO statistics in struct task_io_accounting 2008-07-27 16:12:28 -07:00
uid16.c asmlinkage_protect replaces prevent_tail_call 2008-04-10 17:28:26 -07:00
user.c alloc_uid: cleanup 2008-04-30 08:29:53 -07:00
user_namespace.c eCryptfs: make key module subsystem respect namespaces 2008-04-29 08:06:07 -07:00
utsname.c kernel: explicitly include required header files under kernel/ 2008-04-29 08:06:04 -07:00
utsname_sysctl.c Isolate the UTS namespace's domainname and hostname back 2007-11-29 09:24:53 -08:00
wait.c kernel: remove fastcall in kernel/* 2008-02-08 09:22:31 -08:00
workqueue.c Merge branch 'core/locking' into core/urgent 2008-08-12 00:11:49 +02:00