From 25432ae96a9889774a05bf5f0f6fd8dbcdec5e72 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 8 Jan 2016 11:05:09 +0100 Subject: [PATCH] perf: Optimize perf_sched_events() usage It doesn't make sense to take up-to _4_ references on perf_sched_events() per event, avoid doing this. Signed-off-by: Peter Zijlstra (Intel) Cc: Arnaldo Carvalho de Melo Cc: David Ahern Cc: Jiri Olsa Cc: Linus Torvalds Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Vince Weaver Signed-off-by: Ingo Molnar --- kernel/events/core.c | 22 ++++++++++++++++------ 1 file changed, 16 insertions(+), 6 deletions(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index 079eb9fcaaa8..935aefd16354 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -3491,11 +3491,13 @@ static void unaccount_event_cpu(struct perf_event *event, int cpu) static void unaccount_event(struct perf_event *event) { + bool dec = false; + if (event->parent) return; if (event->attach_state & PERF_ATTACH_TASK) - static_key_slow_dec_deferred(&perf_sched_events); + dec = true; if (event->attr.mmap || event->attr.mmap_data) atomic_dec(&nr_mmap_events); if (event->attr.comm) @@ -3505,12 +3507,15 @@ static void unaccount_event(struct perf_event *event) if (event->attr.freq) atomic_dec(&nr_freq_events); if (event->attr.context_switch) { - static_key_slow_dec_deferred(&perf_sched_events); + dec = true; atomic_dec(&nr_switch_events); } if (is_cgroup_event(event)) - static_key_slow_dec_deferred(&perf_sched_events); + dec = true; if (has_branch_stack(event)) + dec = true; + + if (dec) static_key_slow_dec_deferred(&perf_sched_events); unaccount_event_cpu(event, event->cpu); @@ -7723,11 +7728,13 @@ static void account_event_cpu(struct perf_event *event, int cpu) static void account_event(struct perf_event *event) { + bool inc = false; + if (event->parent) return; if (event->attach_state & PERF_ATTACH_TASK) - static_key_slow_inc(&perf_sched_events.key); + inc = true; if (event->attr.mmap || event->attr.mmap_data) atomic_inc(&nr_mmap_events); if (event->attr.comm) @@ -7740,11 +7747,14 @@ static void account_event(struct perf_event *event) } if (event->attr.context_switch) { atomic_inc(&nr_switch_events); - static_key_slow_inc(&perf_sched_events.key); + inc = true; } if (has_branch_stack(event)) - static_key_slow_inc(&perf_sched_events.key); + inc = true; if (is_cgroup_event(event)) + inc = true; + + if (inc) static_key_slow_inc(&perf_sched_events.key); account_event_cpu(event, event->cpu); -- 2.30.2