From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752101AbdA3L7h (ORCPT ); Mon, 30 Jan 2017 06:59:37 -0500 Received: from terminus.zytor.com ([65.50.211.136]:48118 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753301AbdA3L7O (ORCPT ); Mon, 30 Jan 2017 06:59:14 -0500 Date: Mon, 30 Jan 2017 03:58:35 -0800 From: tip-bot for Alexander Shishkin Message-ID: Cc: linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, jolsa@redhat.com, peterz@infradead.org, acme@infradead.org, vincent.weaver@maine.edu, mingo@kernel.org, eranian@google.com, acme@redhat.com, alexander.shishkin@linux.intel.com, tglx@linutronix.de, hpa@zytor.com, adrian.hunter@intel.com Reply-To: hpa@zytor.com, adrian.hunter@intel.com, alexander.shishkin@linux.intel.com, tglx@linutronix.de, acme@redhat.com, acme@infradead.org, vincent.weaver@maine.edu, torvalds@linux-foundation.org, peterz@infradead.org, linux-kernel@vger.kernel.org, jolsa@redhat.com, eranian@google.com, mingo@kernel.org In-Reply-To: <20170119164330.22887-2-alexander.shishkin@linux.intel.com> References: <20170119164330.22887-2-alexander.shishkin@linux.intel.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:perf/core] perf/core: Don't re-schedule CPU flexible events needlessly Git-Commit-ID: fe45bafbd0e1b5e828aa9d44d07e569df85869a2 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: fe45bafbd0e1b5e828aa9d44d07e569df85869a2 Gitweb: http://git.kernel.org/tip/fe45bafbd0e1b5e828aa9d44d07e569df85869a2 Author: Alexander Shishkin AuthorDate: Thu, 19 Jan 2017 18:43:29 +0200 Committer: Ingo Molnar CommitDate: Mon, 30 Jan 2017 12:01:14 +0100 perf/core: Don't re-schedule CPU flexible events needlessly In the sched-in path, we first remove a CPU's flexible events in order to give priority to the task's pinned events. However, this step can be safely skipped if the task doesn't have its own pinned events. This patch implements this skipping. Reported-by: Adrian Hunter Signed-off-by: Alexander Shishkin Signed-off-by: Peter Zijlstra (Intel) Cc: Arnaldo Carvalho de Melo Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Vince Weaver Cc: vince@deater.net Link: http://lkml.kernel.org/r/20170119164330.22887-2-alexander.shishkin@linux.intel.com Signed-off-by: Ingo Molnar --- 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 d92c7ad..8c0b733 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -3122,8 +3122,12 @@ static void perf_event_context_sched_in(struct perf_event_context *ctx, * We want to keep the following priority order: * cpu pinned (that don't need to move), task pinned, * cpu flexible, task flexible. + * + * However, if task's ctx is not carrying any pinned + * events, no need to flip the cpuctx's events around. */ - cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE); + if (!list_empty(&ctx->pinned_groups)) + cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE); perf_event_sched_in(cpuctx, ctx, task); perf_pmu_enable(ctx->pmu); perf_ctx_unlock(cpuctx, ctx);