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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2009-06-20 21:57:40 +0400 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-06-20 21:57:40 +0400 |
| commit | 1eb51c33b21ffa3fceb634d1d6bcd6488c79bc26 (patch) | |
| tree | 5360e0b439b35a97313ea8250209e7dacff8b9a6 /arch/x86 | |
| parent | b0b7065b64fe517b4a50915a1555e8ee98890d64 (diff) | |
| parent | 3104bf03a923c72043a9c5009d9cd56724304916 (diff) | |
| download | linux-1eb51c33b21ffa3fceb634d1d6bcd6488c79bc26.tar.xz | |
Merge branch 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
sched: Fix out of scope variable access in sched_slice()
sched: Hide runqueues from direct refer at source code level
sched: Remove unneeded __ref tag
sched, x86: Fix cpufreq + sched_clock() TSC scaling
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/include/asm/timer.h | 6 | ||||
| -rw-r--r-- | arch/x86/kernel/tsc.c | 8 |
2 files changed, 11 insertions, 3 deletions
diff --git a/arch/x86/include/asm/timer.h b/arch/x86/include/asm/timer.h index bd37ed444a21..20ca9c4d4686 100644 --- a/arch/x86/include/asm/timer.h +++ b/arch/x86/include/asm/timer.h @@ -45,12 +45,16 @@ extern int no_timer_check; */ DECLARE_PER_CPU(unsigned long, cyc2ns); +DECLARE_PER_CPU(unsigned long long, cyc2ns_offset); #define CYC2NS_SCALE_FACTOR 10 /* 2^10, carefully chosen */ static inline unsigned long long __cycles_2_ns(unsigned long long cyc) { - return cyc * per_cpu(cyc2ns, smp_processor_id()) >> CYC2NS_SCALE_FACTOR; + int cpu = smp_processor_id(); + unsigned long long ns = per_cpu(cyc2ns_offset, cpu); + ns += cyc * per_cpu(cyc2ns, cpu) >> CYC2NS_SCALE_FACTOR; + return ns; } static inline unsigned long long cycles_2_ns(unsigned long long cyc) diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index b0597ad02c93..6e1a368d21d4 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -590,22 +590,26 @@ EXPORT_SYMBOL(recalibrate_cpu_khz); */ DEFINE_PER_CPU(unsigned long, cyc2ns); +DEFINE_PER_CPU(unsigned long long, cyc2ns_offset); static void set_cyc2ns_scale(unsigned long cpu_khz, int cpu) { - unsigned long long tsc_now, ns_now; + unsigned long long tsc_now, ns_now, *offset; unsigned long flags, *scale; local_irq_save(flags); sched_clock_idle_sleep_event(); scale = &per_cpu(cyc2ns, cpu); + offset = &per_cpu(cyc2ns_offset, cpu); rdtscll(tsc_now); ns_now = __cycles_2_ns(tsc_now); - if (cpu_khz) + if (cpu_khz) { *scale = (NSEC_PER_MSEC << CYC2NS_SCALE_FACTOR)/cpu_khz; + *offset = ns_now - (tsc_now * *scale >> CYC2NS_SCALE_FACTOR); + } sched_clock_idle_wakeup_event(0); local_irq_restore(flags); |