diff options
| author | Thomas Gleixner <tglx@linutronix.de> | 2008-12-09 21:43:39 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-12-11 15:45:45 +0100 |
| commit | 4ac13294e44664bb7edf4daf52edb71e7c6bbe84 (patch) | |
| tree | accb533350a655e39a8ab846abc37018b2f87ccf /arch | |
| parent | 43874d238d5f208854a73c3225ca2a22833eec8b (diff) | |
perf counters: protect them against CSTATE transitions
Impact: fix rare lost events problem
There are CPUs whose performance counters misbehave on CSTATE transitions,
so provide a way to just disable/enable them around deep idle methods.
(hw_perf_enable_all() is cheap on x86.)
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kernel/cpu/perf_counter.c | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/arch/x86/kernel/cpu/perf_counter.c b/arch/x86/kernel/cpu/perf_counter.c index 6a93d1f04d9..0a7f3bea2dc 100644 --- a/arch/x86/kernel/cpu/perf_counter.c +++ b/arch/x86/kernel/cpu/perf_counter.c @@ -12,6 +12,7 @@ #include <linux/notifier.h> #include <linux/hardirq.h> #include <linux/kprobes.h> +#include <linux/module.h> #include <linux/kdebug.h> #include <linux/sched.h> @@ -119,10 +120,21 @@ void hw_perf_enable_all(void) wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, perf_counter_mask, 0); } -void hw_perf_disable_all(void) +void hw_perf_restore_ctrl(u64 ctrl) { + wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, ctrl, 0); +} +EXPORT_SYMBOL_GPL(hw_perf_restore_ctrl); + +u64 hw_perf_disable_all(void) +{ + u64 ctrl; + + rdmsrl(MSR_CORE_PERF_GLOBAL_CTRL, ctrl); wrmsr(MSR_CORE_PERF_GLOBAL_CTRL, 0, 0); + return ctrl; } +EXPORT_SYMBOL_GPL(hw_perf_disable_all); static inline void __hw_perf_counter_disable(struct hw_perf_counter *hwc, unsigned int idx) |