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ARM: perf: hook up perf_sample_event_took around pmu irq handling

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Since we indirect all of our PMU IRQ handling through a dispatcher, it's
trivial to hook up perf_sample_event_took to prevent applications such
as oprofile from generating interrupt storms due to an unrealisticly
low sample period.

Reported-by: Robert Richter <rric@kernel.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
This commit is contained in:
Will Deacon 2014-02-11 18:08:41 +00:00
parent d84c47837d
commit 5f5092e72c
1 changed files with 9 additions and 2 deletions
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11
arch/arm/kernel/perf_event.c
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@ -302,6 +302,8 @@ static irqreturn_t armpmu_dispatch_irq(int irq, void *dev)
struct arm_pmu *armpmu;
struct platform_device *plat_device;
struct arm_pmu_platdata *plat;
int ret;
u64 start_clock, finish_clock;
if (irq_is_percpu(irq))
dev = *(void **)dev;
@ -309,10 +311,15 @@ static irqreturn_t armpmu_dispatch_irq(int irq, void *dev)
plat_device = armpmu->plat_device;
plat = dev_get_platdata(&plat_device->dev);
start_clock = sched_clock();
if (plat && plat->handle_irq)
return plat->handle_irq(irq, dev, armpmu->handle_irq);
ret = plat->handle_irq(irq, dev, armpmu->handle_irq);
else
return armpmu->handle_irq(irq, dev);
ret = armpmu->handle_irq(irq, dev);
finish_clock = sched_clock();
perf_sample_event_took(finish_clock - start_clock);
return ret;
}
static void