From 1b9a644fece117cfa5474a2388d6b89d1baf8ddf Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Tue, 7 Sep 2010 18:32:22 +0200 Subject: [PATCH] perf: Optimize context ops Assuming we don't mix events of different pmus onto a single context (with the exeption of software events inside a hardware group) we can now assume that all events on a particular context belong to the same pmu, hence we can disable the pmu for the entire context operations. This reduces the amount of hardware writes. The exception for swevents comes from the fact that the sw pmu disable is a nop. Signed-off-by: Peter Zijlstra Cc: paulus Cc: stephane eranian Cc: Robert Richter Cc: Frederic Weisbecker Cc: Lin Ming Cc: Yanmin LKML-Reference: Signed-off-by: Ingo Molnar --- kernel/perf_event.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/kernel/perf_event.c b/kernel/perf_event.c index 357ee8d5e8ae..9819a69a61a1 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -1065,6 +1065,7 @@ static void ctx_sched_out(struct perf_event_context *ctx, struct perf_event *event; raw_spin_lock(&ctx->lock); + perf_pmu_disable(ctx->pmu); ctx->is_active = 0; if (likely(!ctx->nr_events)) goto out; @@ -1083,6 +1084,7 @@ static void ctx_sched_out(struct perf_event_context *ctx, group_sched_out(event, cpuctx, ctx); } out: + perf_pmu_enable(ctx->pmu); raw_spin_unlock(&ctx->lock); } @@ -1400,6 +1402,7 @@ void perf_event_context_sched_in(struct perf_event_context *ctx) if (cpuctx->task_ctx == ctx) return; + perf_pmu_disable(ctx->pmu); /* * We want to keep the following priority order: * cpu pinned (that don't need to move), task pinned, @@ -1418,6 +1421,7 @@ void perf_event_context_sched_in(struct perf_event_context *ctx) * cpu-context we got scheduled on is actually rotating. */ perf_pmu_rotate_start(ctx->pmu); + perf_pmu_enable(ctx->pmu); } /* @@ -1629,6 +1633,7 @@ static enum hrtimer_restart perf_event_context_tick(struct hrtimer *timer) rotate = 1; } + perf_pmu_disable(cpuctx->ctx.pmu); perf_ctx_adjust_freq(&cpuctx->ctx, cpuctx->timer_interval); if (ctx) perf_ctx_adjust_freq(ctx, cpuctx->timer_interval); @@ -1649,6 +1654,7 @@ static enum hrtimer_restart perf_event_context_tick(struct hrtimer *timer) task_ctx_sched_in(ctx, EVENT_FLEXIBLE); done: + perf_pmu_enable(cpuctx->ctx.pmu); hrtimer_forward_now(timer, ns_to_ktime(cpuctx->timer_interval)); return restart; -- 2.30.2