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Perf: Re-enable counters after power collapse

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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: Ashwin Chaugule <ashwinc@codeaurora.org>
This commit is contained in:
Ashwin Chaugule
2012-08-03 16:30:08 -04:00
committed by Stephen Boyd
parent 5ec4f5b115
commit fe77161b14
2 changed files with 27 additions and 5 deletions
Download Patch File Download Diff File Expand all files Collapse all files

11
arch/arm/include/asm/pmu.h
View File

@@ -108,6 +108,12 @@ struct arm_pmu {
enum arm_pmu_type type; enum arm_pmu_type type;
cpumask_t active_irqs; cpumask_t active_irqs;
const char *name; const 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); irqreturn_t (*handle_irq)(int irq_num, void *dev);
int (*request_pmu_irq)(int irq, irq_handler_t *irq_h); int (*request_pmu_irq)(int irq, irq_handler_t *irq_h);
void (*free_pmu_irq)(int irq); void (*free_pmu_irq)(int irq);
@@ -123,11 +129,6 @@ struct arm_pmu {
void (*stop)(void); void (*stop)(void);
void (*reset)(void *); void (*reset)(void *);
int (*map_event)(struct perf_event *event); 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); struct pmu_hw_events *(*get_hw_events)(void);
int (*test_set_event_constraints)(struct perf_event *event); int (*test_set_event_constraints)(struct perf_event *event);
int (*clear_event_constraints)(struct perf_event *event); int (*clear_event_constraints)(struct perf_event *event);

21
arch/arm/kernel/perf_event.c
View File

@@ -600,6 +600,21 @@ static void armpmu_enable(struct pmu *pmu)
struct arm_pmu *armpmu = to_arm_pmu(pmu); struct arm_pmu *armpmu = to_arm_pmu(pmu);
struct pmu_hw_events *hw_events = armpmu->get_hw_events(); struct pmu_hw_events *hw_events = armpmu->get_hw_events();
int enabled = bitmap_weight(hw_events->used_mask, armpmu->num_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) if (enabled)
armpmu->start(); armpmu->start();
@@ -716,6 +731,7 @@ static void __init cpu_pmu_init(struct arm_pmu *armpmu)
* UNKNOWN at reset, the PMU must be explicitly reset to avoid reading * UNKNOWN at reset, the PMU must be explicitly reset to avoid reading
* junk values out of them. * junk values out of them.
*/ */
static int __cpuinit pmu_cpu_notify(struct notifier_block *b, static int __cpuinit pmu_cpu_notify(struct notifier_block *b,
unsigned long action, void *hcpu) unsigned long action, void *hcpu)
{ {
@@ -785,6 +801,11 @@ static int perf_cpu_pm_notifier(struct notifier_block *self, unsigned long cmd,
case CPU_PM_ENTER_FAILED: case CPU_PM_ENTER_FAILED:
case CPU_PM_EXIT: case CPU_PM_EXIT:
if (cpu_has_active_perf() && cpu_pmu->reset) { 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); cpu_pmu->reset(NULL);
perf_pmu_enable(&cpu_pmu->pmu); perf_pmu_enable(&cpu_pmu->pmu);
} }