From a4eaf7f14675cb512d69f0c928055e73d0c6d252 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Wed, 16 Jun 2010 14:37:10 +0200 Subject: perf: Rework the PMU methods Replace pmu::{enable,disable,start,stop,unthrottle} with pmu::{add,del,start,stop}, all of which take a flags argument. The new interface extends the capability to stop a counter while keeping it scheduled on the PMU. We replace the throttled state with the generic stopped state. This also allows us to efficiently stop/start counters over certain code paths (like IRQ handlers). It also allows scheduling a counter without it starting, allowing for a generic frozen state (useful for rotating stopped counters). The stopped state is implemented in two different ways, depending on how the architecture implemented the throttled state: 1) We disable the counter: a) the pmu has per-counter enable bits, we flip that b) we program a NOP event, preserving the counter state 2) We store the counter state and ignore all read/overflow events Signed-off-by: Peter Zijlstra Cc: paulus Cc: stephane eranian Cc: Robert Richter Cc: Will Deacon Cc: Paul Mundt Cc: Frederic Weisbecker Cc: Cyrill Gorcunov Cc: Lin Ming Cc: Yanmin Cc: Deng-Cheng Zhu Cc: David Miller Cc: Michael Cree LKML-Reference: Signed-off-by: Ingo Molnar --- arch/sparc/kernel/perf_event.c | 109 +++++++++++++++++++++++++---------------- 1 file changed, 67 insertions(+), 42 deletions(-) (limited to 'arch/sparc/kernel') diff --git a/arch/sparc/kernel/perf_event.c b/arch/sparc/kernel/perf_event.c index 37cae676536c..516be2314b54 100644 --- a/arch/sparc/kernel/perf_event.c +++ b/arch/sparc/kernel/perf_event.c @@ -658,13 +658,16 @@ static u64 maybe_change_configuration(struct cpu_hw_events *cpuc, u64 pcr) enc = perf_event_get_enc(cpuc->events[i]); pcr &= ~mask_for_index(idx); - pcr |= event_encoding(enc, idx); + if (hwc->state & PERF_HES_STOPPED) + pcr |= nop_for_index(idx); + else + pcr |= event_encoding(enc, idx); } out: return pcr; } -static void sparc_pmu_pmu_enable(struct pmu *pmu) +static void sparc_pmu_enable(struct pmu *pmu) { struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events); u64 pcr; @@ -691,7 +694,7 @@ static void sparc_pmu_pmu_enable(struct pmu *pmu) pcr_ops->write(cpuc->pcr); } -static void sparc_pmu_pmu_disable(struct pmu *pmu) +static void sparc_pmu_disable(struct pmu *pmu) { struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events); u64 val; @@ -710,10 +713,53 @@ static void sparc_pmu_pmu_disable(struct pmu *pmu) pcr_ops->write(cpuc->pcr); } -static void sparc_pmu_disable(struct perf_event *event) +static int active_event_index(struct cpu_hw_events *cpuc, + struct perf_event *event) +{ + int i; + + for (i = 0; i < cpuc->n_events; i++) { + if (cpuc->event[i] == event) + break; + } + BUG_ON(i == cpuc->n_events); + return cpuc->current_idx[i]; +} + +static void sparc_pmu_start(struct perf_event *event, int flags) +{ + struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events); + int idx = active_event_index(cpuc, event); + + if (flags & PERF_EF_RELOAD) { + WARN_ON_ONCE(!(event->hw.state & PERF_HES_UPTODATE)); + sparc_perf_event_set_period(event, &event->hw, idx); + } + + event->hw.state = 0; + + sparc_pmu_enable_event(cpuc, &event->hw, idx); +} + +static void sparc_pmu_stop(struct perf_event *event, int flags) +{ + struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events); + int idx = active_event_index(cpuc, event); + + if (!(event->hw.state & PERF_HES_STOPPED)) { + sparc_pmu_disable_event(cpuc, &event->hw, idx); + event->hw.state |= PERF_HES_STOPPED; + } + + if (!(event->hw.state & PERF_HES_UPTODATE) && (flags & PERF_EF_UPDATE)) { + sparc_perf_event_update(event, &event->hw, idx); + event->hw.state |= PERF_HES_UPTODATE; + } +} + +static void sparc_pmu_del(struct perf_event *event, int _flags) { struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events); - struct hw_perf_event *hwc = &event->hw; unsigned long flags; int i; @@ -722,7 +768,10 @@ static void sparc_pmu_disable(struct perf_event *event) for (i = 0; i < cpuc->n_events; i++) { if (event == cpuc->event[i]) { - int idx = cpuc->current_idx[i]; + /* Absorb the final count and turn off the + * event. + */ + sparc_pmu_stop(event, PERF_EF_UPDATE); /* Shift remaining entries down into * the existing slot. @@ -734,13 +783,6 @@ static void sparc_pmu_disable(struct perf_event *event) cpuc->current_idx[i]; } - /* Absorb the final count and turn off the - * event. - */ - sparc_pmu_disable_event(cpuc, hwc, idx); - barrier(); - sparc_perf_event_update(event, hwc, idx); - perf_event_update_userpage(event); cpuc->n_events--; @@ -752,19 +794,6 @@ static void sparc_pmu_disable(struct perf_event *event) local_irq_restore(flags); } -static int active_event_index(struct cpu_hw_events *cpuc, - struct perf_event *event) -{ - int i; - - for (i = 0; i < cpuc->n_events; i++) { - if (cpuc->event[i] == event) - break; - } - BUG_ON(i == cpuc->n_events); - return cpuc->current_idx[i]; -} - static void sparc_pmu_read(struct perf_event *event) { struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events); @@ -774,15 +803,6 @@ static void sparc_pmu_read(struct perf_event *event) sparc_perf_event_update(event, hwc, idx); } -static void sparc_pmu_unthrottle(struct perf_event *event) -{ - struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events); - int idx = active_event_index(cpuc, event); - struct hw_perf_event *hwc = &event->hw; - - sparc_pmu_enable_event(cpuc, hwc, idx); -} - static atomic_t active_events = ATOMIC_INIT(0); static DEFINE_MUTEX(pmc_grab_mutex); @@ -984,7 +1004,7 @@ static int collect_events(struct perf_event *group, int max_count, return n; } -static int sparc_pmu_enable(struct perf_event *event) +static int sparc_pmu_add(struct perf_event *event, int ef_flags) { struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events); int n0, ret = -EAGAIN; @@ -1001,6 +1021,10 @@ static int sparc_pmu_enable(struct perf_event *event) cpuc->events[n0] = event->hw.event_base; cpuc->current_idx[n0] = PIC_NO_INDEX; + event->hw.state = PERF_HES_UPTODATE; + if (!(ef_flags & PERF_EF_START)) + event->hw.state |= PERF_HES_STOPPED; + /* * If group events scheduling transaction was started, * skip the schedulability test here, it will be peformed @@ -1156,13 +1180,14 @@ static int sparc_pmu_commit_txn(struct pmu *pmu) } static struct pmu pmu = { - .pmu_enable = sparc_pmu_pmu_enable, - .pmu_disable = sparc_pmu_pmu_disable, + .pmu_enable = sparc_pmu_enable, + .pmu_disable = sparc_pmu_disable, .event_init = sparc_pmu_event_init, - .enable = sparc_pmu_enable, - .disable = sparc_pmu_disable, + .add = sparc_pmu_add, + .del = sparc_pmu_del, + .start = sparc_pmu_start, + .stop = sparc_pmu_stop, .read = sparc_pmu_read, - .unthrottle = sparc_pmu_unthrottle, .start_txn = sparc_pmu_start_txn, .cancel_txn = sparc_pmu_cancel_txn, .commit_txn = sparc_pmu_commit_txn, @@ -1243,7 +1268,7 @@ static int __kprobes perf_event_nmi_handler(struct notifier_block *self, continue; if (perf_event_overflow(event, 1, &data, regs)) - sparc_pmu_disable_event(cpuc, hwc, idx); + sparc_pmu_stop(event, 0); } return NOTIFY_STOP; -- cgit v1.2.3-59-g8ed1b