On Tue, Feb 11, 2014 at 04:33:51AM +0000, Weng Meiling wrote: > Hi Will,
Hello, > >>> how userland can be notified about throttling. Throttling could be > >>> worth for operf too, not only for the oprofile kernel driver. > >>> > > > >>> From a quick look it seems there is also code in x86 that dynamically > >>> adjusts the rate which might be worth being implemented for ARM too. > >> > >> Are you referring to the perf_sample_event_took callback? If so, that > >> certainly looks worth persuing. I'll stick it on my list, thanks! > >> > > Is there any progress on this work? Because this is important for me. > Sorry for trouble you. Oops, I totally forgot about this. Does the below patch work for you? Will --->8 diff --git a/arch/arm/kernel/perf_event.c b/arch/arm/kernel/perf_event.c index 361a1aaee7c8..a6bc431cde70 100644 --- a/arch/arm/kernel/perf_event.c +++ b/arch/arm/kernel/perf_event.c @@ -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 diff --git a/kernel/events/core.c b/kernel/events/core.c index 56003c6edfd3..6fcc293d77a4 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -237,6 +237,8 @@ void perf_sample_event_took(u64 sample_len_ns) u64 local_samples_len; u64 allowed_ns = ACCESS_ONCE(perf_sample_allowed_ns); + pr_info("perf_sample_event_took(%llu ns)\n", sample_len_ns); + if (allowed_ns == 0) return; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/