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authorLorenzo Pieralisi <lorenzo.pieralisi@arm.com>2016-02-23 18:22:39 +0000
committerWill Deacon <will.deacon@arm.com>2016-02-26 14:37:06 +0000
commitda4e4f18afe0f3729d68f3785c5802f786d36e34 (patch)
tree79bea24abaddb8f5c7ed32b763dbb182a5e072bb /include/linux/perf
parent94085fe570e7b87597d4695e6fa77d4256efd29e (diff)
downloadop-kernel-dev-da4e4f18afe0f3729d68f3785c5802f786d36e34.zip
op-kernel-dev-da4e4f18afe0f3729d68f3785c5802f786d36e34.tar.gz
drivers/perf: arm_pmu: implement CPU_PM notifier
When a CPU is suspended (either through suspend-to-RAM or CPUidle), its PMU registers content can be lost, which means that counters registers values that were initialized on power down entry have to be reprogrammed on power-up to make sure the counters set-up is preserved (ie on power-up registers take the reset values on Cold or Warm reset, which can be architecturally UNKNOWN). To guarantee seamless profiling conditions across a core power down this patch adds a CPU PM notifier to ARM pmus, that upon CPU PM entry/exit from low-power states saves/restores the pmu registers set-up (by using the ARM perf API), so that the power-down/up cycle does not affect the perf behaviour (apart from a black-out period between power-up/down CPU PM notifications that is unavoidable). Cc: Will Deacon <will.deacon@arm.com> Cc: Sudeep Holla <sudeep.holla@arm.com> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Mathieu Poirier <mathieu.poirier@linaro.org> Cc: Mark Rutland <mark.rutland@arm.com> Acked-by: Ashwin Chaugule <ashwin.chaugule@linaro.org> Acked-by: Kevin Hilman <khilman@baylibre.com> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'include/linux/perf')
-rw-r--r--include/linux/perf/arm_pmu.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/perf/arm_pmu.h b/include/linux/perf/arm_pmu.h
index 2d5eaaa..4196c90 100644
--- a/include/linux/perf/arm_pmu.h
+++ b/include/linux/perf/arm_pmu.h
@@ -108,6 +108,7 @@ struct arm_pmu {
struct platform_device *plat_device;
struct pmu_hw_events __percpu *hw_events;
struct notifier_block hotplug_nb;
+ struct notifier_block cpu_pm_nb;
};
#define to_arm_pmu(p) (container_of(p, struct arm_pmu, pmu))
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