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>
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@ -10180,7 +10180,16 @@ got_cpu_context:
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if (!pmu->event_idx)
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pmu->event_idx = perf_event_idx_default;
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list_add_rcu(&pmu->entry, &pmus);
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/*
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* Ensure the TYPE_SOFTWARE PMUs are at the head of the list,
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* since these cannot be in the IDR. This way the linear search
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* is fast, provided a valid software event is provided.
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*/
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if (type == PERF_TYPE_SOFTWARE || !name)
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list_add_rcu(&pmu->entry, &pmus);
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else
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list_add_tail_rcu(&pmu->entry, &pmus);
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atomic_set(&pmu->exclusive_cnt, 0);
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ret = 0;
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unlock:
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