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linux/arch/x86_64/kernel
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Dimitri Sivanich cbf9b4bb76 [PATCH] X86_64 monotonic_clock goes backwards 
I've noticed some erratic behavior while testing the X86_64 version
of monotonic_clock().

While spinning in a loop reading monotonic clock values (pinned to a
single cpu) I noticed that the difference between subsequent values
occasionally went negative (time going backwards).

I found that in the following code:
                this_offset = get_cycles_sync();
                /* FIXME: 1000 or 1000000? */
-->             offset = (this_offset - last_offset)*1000 / cpu_khz;
        }
        return base + offset;

the offset sometimes turns out to be 0, even though
this_offset > last_offset.

+Added fix From: Toyo Abe <toyoa@mvista.com>

The x86_64-mm-monotonic-clock.patch in 2.6.18-rc4-mm2 made a change to
the updating of monotonic_base. It now uses cycles_2_ns().

I suggest that a set_cyc2ns_scale() should be done prior to the setup_irq().
Because cycles_2_ns() can be called from the timer ISR right after the irq0
is enabled.

Signed-off-by: Toyo Abe <toyoa@mvista.com>
Signed-off-by: Dimitri Sivanich <sivanich@sgi.com>
Signed-off-by: Andi Kleen <ak@suse.de>
2006-09-26 10:52:34 +02:00
..
acpi Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
cpufreq Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
aperture.c [PATCH] A few trivial spelling and grammar fixes 2006-09-26 10:52:28 +02:00
apic.c [PATCH] Don't access the APIC in safe_smp_processor_id when it is not mapped yet 2006-09-26 10:52:34 +02:00
asm-offsets.c [CRYPTO] all: Pass tfm instead of ctx to algorithms 2006-06-26 17:34:39 +10:00
audit.c [PATCH] audit: AUDIT_PERM support 2006-09-11 13:32:30 -04:00
crash.c [PATCH] Remove all ifdefs for local/io apic 2006-09-26 10:52:29 +02:00
crash_dump.c [PATCH] kdump: read previous kernel's memory 2006-01-10 08:01:28 -08:00
e820.c [PATCH] Move e820 map into e820.c 2006-09-26 10:52:33 +02:00
early-quirks.c [PATCH] Move early chipset quirks out to new file 2006-09-26 10:52:30 +02:00
early_printk.c [PATCH] Convert x86-64 to early param 2006-09-26 10:52:32 +02:00
entry.S [PATCH] x86: error_code is not safe for kprobes 2006-09-26 10:52:34 +02:00
functionlist [NET]: make skb_release_data() static 2006-06-29 16:58:30 -07:00
genapic.c Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
genapic_cluster.c [PATCH] remove int_delivery_dest 2006-09-26 10:52:31 +02:00
genapic_flat.c [PATCH] Replace local_save_flags+local_irq_disable with 2006-09-26 10:52:33 +02:00
head.S [PATCH] Remove obsolete CVS $Id$ from assembler files in arch/x86_64/kernel/* 2006-09-26 10:52:31 +02:00
head64.c [PATCH] Remove need for early lockdep init 2006-09-26 10:52:32 +02:00
i387.c Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
i8259.c [PATCH] Remove all ifdefs for local/io apic 2006-09-26 10:52:29 +02:00
init_task.c [PATCH] x86_64: Save original IST values for checking stack addresses 2006-08-30 16:05:16 -07:00
io_apic.c [PATCH] Convert x86-64 to early param 2006-09-26 10:52:32 +02:00
ioport.c [PATCH] x86-64 TIF flags for debug regs and io bitmap in ctxsw 2006-09-26 10:52:28 +02:00
irq.c [PATCH] Remove apic mismatch counter 2006-09-26 10:52:29 +02:00
k8.c [PATCH] x86_64: Clean and enhance up K8 northbridge access code 2006-06-26 10:48:15 -07:00
kprobes.c Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
ldt.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
machine_kexec.c [PATCH] Convert x86-64 to early param 2006-09-26 10:52:32 +02:00
Makefile [PATCH] Move early chipset quirks out to new file 2006-09-26 10:52:30 +02:00
mce.c [PATCH] cpu hotplug: use hotplug version of registration in late inits 2006-07-31 13:28:39 -07:00
mce_amd.c [PATCH] cpu hotplug: use hotplug version of registration in late inits 2006-07-31 13:28:39 -07:00
mce_intel.c [PATCH] x86_64: Some housekeeping in local APIC code 2006-01-11 19:05:03 -08:00
module.c [PATCH] x86_64: x86_64 version of the smp alternative patch. 2006-06-26 10:48:14 -07:00
mpparse.c [PATCH] Fix up some non linuxy style in ACPI functions in mpparse.c 2006-09-26 10:52:30 +02:00
nmi.c [PATCH] x86: i386/x86-64 Add nmi watchdog support for new Intel CPUs 2006-09-26 10:52:27 +02:00
pci-calgary.c [PATCH] Calgary IOMMU: eradicate sole remaining 80 chars per line offender 2006-09-26 10:52:33 +02:00
pci-dma.c [PATCH] Convert x86-64 to early param 2006-09-26 10:52:32 +02:00
pci-gart.c [PATCH] remove superflous BUG_ON's in nommu and gart 2006-09-26 10:52:32 +02:00
pci-nommu.c [PATCH] remove superflous BUG_ON's in nommu and gart 2006-09-26 10:52:32 +02:00
pci-swiotlb.c [PATCH] x86_64: Fix swiotlb=force 2006-07-29 20:59:55 -07:00
pmtimer.c [PATCH] make pmtmr_ioport __read_mostly 2006-06-26 09:58:21 -07:00
process.c [PATCH] i386/x86-64: Don't randomize stack top when no randomization personality is set 2006-09-26 10:52:28 +02:00
ptrace.c [PATCH] i386/x86-64: rename is_at_popf(), add iret to tests and fix 2006-09-26 10:52:33 +02:00
reboot.c [PATCH] x86_64: Move export symbols to their C functions 2006-06-26 10:48:22 -07:00
relocate_kernel.S [PATCH] kexec: x86_64 kexec implementation 2005-06-25 16:24:50 -07:00
setup.c [PATCH] Move e820 map into e820.c 2006-09-26 10:52:33 +02:00
setup64.c [PATCH] Convert x86-64 to early param 2006-09-26 10:52:32 +02:00
signal.c [PATCH] Add TIF_RESTORE_SIGMASK 2006-09-26 10:52:26 +02:00
smp.c [PATCH] Don't access the APIC in safe_smp_processor_id when it is not mapped yet 2006-09-26 10:52:34 +02:00
smpboot.c [PATCH] Convert x86-64 to early param 2006-09-26 10:52:32 +02:00
stacktrace.c [PATCH] Merge stacktrace and show_trace 2006-09-26 10:52:34 +02:00
suspend.c Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
suspend_asm.S [PATCH] x86_64: Set up safe page tables during resume 2005-10-10 08:36:46 -07:00
sys_x86_64.c [PATCH] x86_64: Use common sys_time64 2005-11-14 19:55:17 -08:00
syscall.c Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
tce.c [PATCH] Calgary IOMMU: consolidate per bus data structures 2006-09-26 10:52:31 +02:00
time.c [PATCH] X86_64 monotonic_clock goes backwards 2006-09-26 10:52:34 +02:00
trampoline.S [PATCH] Fix gdt table size in trampoline.S 2006-09-26 10:52:32 +02:00
traps.c [PATCH] Check for end of stack trace before falling back 2006-09-26 10:52:34 +02:00
vmlinux.lds.S [PATCH] Add the vgetcpu vsyscall 2006-09-26 10:52:28 +02:00
vsmp.c [PATCH] x86_64: Inclusion of ScaleMP vSMP architecture patches - vsmp_arch 2006-01-11 19:05:01 -08:00
vsyscall.c [PATCH] Add sparse annotation to vsyscall.c 2006-09-26 10:52:33 +02:00
x8664_ksyms.c [PATCH] x86_64: Move export symbols to their C functions 2006-06-26 10:48:22 -07:00