diff options
| author | Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> | 2016-02-23 18:22:39 +0000 |
|---|---|---|
| committer | Kyle Yan <kyan@codeaurora.org> | 2016-04-27 19:05:05 -0700 |
| commit | 8eb64466739b7ae62aa856e72fd4723c358b5544 (patch) | |
| tree | 42fab98474a5eeb5632ee7ab50295dd798a087c3 /include/linux | |
| parent | 898d8c18fadd780d4b66099f14696f654b0afc8b (diff) | |
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>
Git-commit: da4e4f18afe0f3729d68f3785c5802f786d36e34
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
CRs-Fixed: 1008368
Change-Id: I2901cd11e3832ef671581ac6e4f0e3edce630e6d
Signed-off-by: Jeremy Gebben <jgebben@codeaurora.org>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/perf/arm_pmu.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/perf/arm_pmu.h b/include/linux/perf/arm_pmu.h index 1e0cb45e9215..654bb97a3188 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)) |