diff options
| -rw-r--r-- | arch/x86/kernel/cpu/perf_event_intel_rapl.c | 74 |
1 files changed, 72 insertions, 2 deletions
diff --git a/arch/x86/kernel/cpu/perf_event_intel_rapl.c b/arch/x86/kernel/cpu/perf_event_intel_rapl.c index cfcd386b5d89..bf8e4a736d48 100644 --- a/arch/x86/kernel/cpu/perf_event_intel_rapl.c +++ b/arch/x86/kernel/cpu/perf_event_intel_rapl.c @@ -96,6 +96,8 @@ struct rapl_pmu { int n_active; /* number of active events */ struct list_head active_list; struct pmu *pmu; /* pointer to rapl_pmu_class */ + ktime_t timer_interval; /* in ktime_t unit */ + struct hrtimer hrtimer; }; static struct pmu rapl_pmu_class; @@ -158,6 +160,48 @@ again: return new_raw_count; } +static void rapl_start_hrtimer(struct rapl_pmu *pmu) +{ + __hrtimer_start_range_ns(&pmu->hrtimer, + pmu->timer_interval, 0, + HRTIMER_MODE_REL_PINNED, 0); +} + +static void rapl_stop_hrtimer(struct rapl_pmu *pmu) +{ + hrtimer_cancel(&pmu->hrtimer); +} + +static enum hrtimer_restart rapl_hrtimer_handle(struct hrtimer *hrtimer) +{ + struct rapl_pmu *pmu = __get_cpu_var(rapl_pmu); + struct perf_event *event; + unsigned long flags; + + if (!pmu->n_active) + return HRTIMER_NORESTART; + + spin_lock_irqsave(&pmu->lock, flags); + + list_for_each_entry(event, &pmu->active_list, active_entry) { + rapl_event_update(event); + } + + spin_unlock_irqrestore(&pmu->lock, flags); + + hrtimer_forward_now(hrtimer, pmu->timer_interval); + + return HRTIMER_RESTART; +} + +static void rapl_hrtimer_init(struct rapl_pmu *pmu) +{ + struct hrtimer *hr = &pmu->hrtimer; + + hrtimer_init(hr, CLOCK_MONOTONIC, HRTIMER_MODE_REL); + hr->function = rapl_hrtimer_handle; +} + static void __rapl_pmu_event_start(struct rapl_pmu *pmu, struct perf_event *event) { @@ -171,6 +215,8 @@ static void __rapl_pmu_event_start(struct rapl_pmu *pmu, local64_set(&event->hw.prev_count, rapl_read_counter(event)); pmu->n_active++; + if (pmu->n_active == 1) + rapl_start_hrtimer(pmu); } static void rapl_pmu_event_start(struct perf_event *event, int mode) @@ -195,6 +241,8 @@ static void rapl_pmu_event_stop(struct perf_event *event, int mode) if (!(hwc->state & PERF_HES_STOPPED)) { WARN_ON_ONCE(pmu->n_active <= 0); pmu->n_active--; + if (pmu->n_active == 0) + rapl_stop_hrtimer(pmu); list_del(&event->active_entry); @@ -423,6 +471,9 @@ static void rapl_cpu_exit(int cpu) */ if (target >= 0) perf_pmu_migrate_context(pmu->pmu, cpu, target); + + /* cancel overflow polling timer for CPU */ + rapl_stop_hrtimer(pmu); } static void rapl_cpu_init(int cpu) @@ -442,6 +493,7 @@ static int rapl_cpu_prepare(int cpu) { struct rapl_pmu *pmu = per_cpu(rapl_pmu, cpu); int phys_id = topology_physical_package_id(cpu); + u64 ms; if (pmu) return 0; @@ -466,6 +518,22 @@ static int rapl_cpu_prepare(int cpu) pmu->hw_unit = (pmu->hw_unit >> 8) & 0x1FULL; pmu->pmu = &rapl_pmu_class; + /* + * use reference of 200W for scaling the timeout + * to avoid missing counter overflows. + * 200W = 200 Joules/sec + * divide interval by 2 to avoid lockstep (2 * 100) + * if hw unit is 32, then we use 2 ms 1/200/2 + */ + if (pmu->hw_unit < 32) + ms = (1000 / (2 * 100)) * (1ULL << (32 - pmu->hw_unit - 1)); + else + ms = 2; + + pmu->timer_interval = ms_to_ktime(ms); + + rapl_hrtimer_init(pmu); + /* set RAPL pmu for this cpu for now */ per_cpu(rapl_pmu, cpu) = pmu; per_cpu(rapl_pmu_to_free, cpu) = NULL; @@ -580,9 +648,11 @@ static int __init rapl_pmu_init(void) pr_info("RAPL PMU detected, hw unit 2^-%d Joules," " API unit is 2^-32 Joules," - " %d fixed counters\n", + " %d fixed counters" + " %llu ms ovfl timer\n", pmu->hw_unit, - hweight32(rapl_cntr_mask)); + hweight32(rapl_cntr_mask), + ktime_to_ms(pmu->timer_interval)); put_online_cpus(); |