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Date: Wed, 11 Dec 2013 15:10:50 +0800 From: "Yan, Zheng" <zheng.z.yan@...el.com> To: linux-kernel@...r.kernel.org Cc: a.p.zijlstra@...llo.nl, eranian@...gle.com, andi@...stfloor.org, "Yan, Zheng" <zheng.z.yan@...el.com> Subject: [PATCH 05/15] perf, core: Optimize context switch callback invoking From: "Yan, Zheng" <zheng.z.yan@...el.com> So far only CPU pmu uses context switch callback and it is the first registered pmu. So we can avoid iterating the whole pmu list. Signed-off-by: Yan, Zheng <zheng.z.yan@...el.com> --- kernel/events/core.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index fc97ed6..c281265 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -2373,6 +2373,10 @@ static void perf_pmu_sched_task(struct task_struct *prev, perf_pmu_enable(pmu); perf_ctx_unlock(cpuctx, cpuctx->task_ctx); + + /* so far only CPU pmu uses context switch callback */ + if (++count >= __get_cpu_var(perf_sched_cb_usages)) + break; } rcu_read_unlock(); @@ -6492,7 +6496,7 @@ got_cpu_context: if (!pmu->event_idx) pmu->event_idx = perf_event_idx_default; - list_add_rcu(&pmu->entry, &pmus); + list_add_tail_rcu(&pmu->entry, &pmus); ret = 0; unlock: mutex_unlock(&pmus_lock); -- 1.8.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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