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Commit d3b27cc5 authored by Ashwin Chaugule's avatar Ashwin Chaugule Committed by Stephen Boyd
Browse files

Perf: Re-enable counters after power collapse 



Counters need to be individually re-enabled after the CPU
comes out of power collapse. Without this the counters
will simply be set to their MAX period and starting the PMU
will have no effect.

Change-Id: I3988a45277057eb80cf580b90ce697d0e6a00c43
Signed-off-by: default avatarAshwin Chaugule <ashwinc@codeaurora.org>
parent 38655ce3

arch/arm/include/asm/pmu.h

+6 −5
Original line number Diff line number Diff line
@@ -76,6 +76,12 @@ struct arm_pmu { 
	struct pmu	pmu;

	cpumask_t	active_irqs;

	char		*name;

	int		num_events;

	atomic_t	active_events;

	struct mutex	reserve_mutex;

	u64		max_period;

	struct platform_device	*plat_device;

	u32		from_idle;

	irqreturn_t	(*handle_irq)(int irq_num, void *dev);

	void		(*enable)(struct perf_event *event);

	void		(*disable)(struct perf_event *event);
@@ -91,11 +97,6 @@ struct arm_pmu { 
	int		(*request_irq)(struct arm_pmu *, irq_handler_t handler);

	void		(*free_irq)(struct arm_pmu *);

	int		(*map_event)(struct perf_event *event);

	int		num_events;

	atomic_t	active_events;

	struct mutex	reserve_mutex;

	u64		max_period;

	struct platform_device	*plat_device;

	struct pmu_hw_events	*(*get_hw_events)(void);

	int	(*test_set_event_constraints)(struct perf_event *event);

	int	(*clear_event_constraints)(struct perf_event *event);

arch/arm/kernel/perf_event.c

+15 −0
Original line number Diff line number Diff line
@@ -467,6 +467,21 @@ static void armpmu_enable(struct pmu *pmu) 
	struct arm_pmu *armpmu = to_arm_pmu(pmu);

	struct pmu_hw_events *hw_events = armpmu->get_hw_events();

	int enabled = bitmap_weight(hw_events->used_mask, armpmu->num_events);

	int idx;



	if (armpmu->from_idle) {

		for (idx = 0; idx <= cpu_pmu->num_events; ++idx) {

			struct perf_event *event = hw_events->events[idx];



			if (!event)

				continue;



			armpmu->enable(&event->hw, idx, event->cpu);

		}



		/* Reset bit so we don't needlessly re-enable counters.*/

		armpmu->from_idle = 0;

	}



	if (enabled)

		armpmu->start(armpmu);

arch/arm/kernel/perf_event_cpu.c

+6 −0
Original line number Diff line number Diff line
@@ -231,10 +231,16 @@ static int perf_cpu_pm_notifier(struct notifier_block *self, unsigned long cmd, 
	case CPU_PM_ENTER_FAILED:

	case CPU_PM_EXIT:

		if (cpu_has_active_perf() && cpu_pmu->reset) {

			/*

			 * Flip this bit so armpmu_enable knows it needs

			 * to re-enable active counters.

			 */

			cpu_pmu->from_idle = 1;

			cpu_pmu->reset(NULL);

			perf_pmu_enable(&cpu_pmu->pmu);

		}

		break;

		break;

	}



	return NOTIFY_OK;