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 /drivers | |
| parent | perfcounters: consolidate global-disable codepaths (diff) | |
| download | linux-4ac13294e44664bb7edf4daf52edb71e7c6bbe84.tar.xz linux-4ac13294e44664bb7edf4daf52edb71e7c6bbe84.zip | |
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 'drivers')
| -rw-r--r-- | drivers/acpi/processor_idle.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c index 5f8d746a9b81..cca804e6f1dd 100644 --- a/drivers/acpi/processor_idle.c +++ b/drivers/acpi/processor_idle.c @@ -270,8 +270,11 @@ static atomic_t c3_cpu_count; /* Common C-state entry for C2, C3, .. */ static void acpi_cstate_enter(struct acpi_processor_cx *cstate) { + u64 pctrl; + /* Don't trace irqs off for idle */ stop_critical_timings(); + pctrl = hw_perf_disable_all(); if (cstate->entry_method == ACPI_CSTATE_FFH) { /* Call into architectural FFH based C-state */ acpi_processor_ffh_cstate_enter(cstate); @@ -284,6 +287,7 @@ static void acpi_cstate_enter(struct acpi_processor_cx *cstate) gets asserted in time to freeze execution properly. */ unused = inl(acpi_gbl_FADT.xpm_timer_block.address); } + hw_perf_restore_ctrl(pctrl); start_critical_timings(); } #endif /* !CONFIG_CPU_IDLE */ @@ -1425,8 +1429,11 @@ static inline void acpi_idle_update_bm_rld(struct acpi_processor *pr, */ static inline void acpi_idle_do_entry(struct acpi_processor_cx *cx) { + u64 pctrl; + /* Don't trace irqs off for idle */ stop_critical_timings(); + pctrl = hw_perf_disable_all(); if (cx->entry_method == ACPI_CSTATE_FFH) { /* Call into architectural FFH based C-state */ acpi_processor_ffh_cstate_enter(cx); @@ -1441,6 +1448,7 @@ static inline void acpi_idle_do_entry(struct acpi_processor_cx *cx) gets asserted in time to freeze execution properly. */ unused = inl(acpi_gbl_FADT.xpm_timer_block.address); } + hw_perf_restore_ctrl(pctrl); start_critical_timings(); } |