diff options
| author | Liang, Kan <kan.liang@linux.intel.com> | 2019-10-22 12:13:09 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2019-10-28 14:53:28 +0300 |
| commit | d44f821b0e13275735e8f3fe4db8703b45f05d52 (patch) | |
| tree | 26342e8b5b15c28b00b2b3a6557de5e1a85b2f19 /kernel/events | |
| parent | 66d258c5b048840991de49697264af75f5b09def (diff) | |
| download | linux-d44f821b0e13275735e8f3fe4db8703b45f05d52.tar.xz | |
perf/core: Optimize perf_init_event() for TYPE_SOFTWARE
Andi reported that he was hitting the linear search in
perf_init_event() a lot. Now that all !TYPE_SOFTWARE events should hit
the IDR, make sure the TYPE_SOFTWARE events are at the head of the
list such that we'll quickly find the right PMU (provided a valid
event was given).
Signed-off-by: Liang, Kan <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/events')
| -rw-r--r-- | kernel/events/core.c | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c index 4d67c5d35c13..cfd89b4a02d8 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -10180,7 +10180,16 @@ got_cpu_context: if (!pmu->event_idx) pmu->event_idx = perf_event_idx_default; - list_add_rcu(&pmu->entry, &pmus); + /* + * Ensure the TYPE_SOFTWARE PMUs are at the head of the list, + * since these cannot be in the IDR. This way the linear search + * is fast, provided a valid software event is provided. + */ + if (type == PERF_TYPE_SOFTWARE || !name) + list_add_rcu(&pmu->entry, &pmus); + else + list_add_tail_rcu(&pmu->entry, &pmus); + atomic_set(&pmu->exclusive_cnt, 0); ret = 0; unlock: |