From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754194Ab3LRKdU (ORCPT ); Wed, 18 Dec 2013 05:33:20 -0500 Received: from terminus.zytor.com ([198.137.202.10]:44714 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751196Ab3LRKdQ (ORCPT ); Wed, 18 Dec 2013 05:33:16 -0500 Date: Wed, 18 Dec 2013 02:32:30 -0800 From: tip-bot for Peter Zijlstra Message-ID: Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@kernel.org, vincent.weaver@maine.edu, will.deacon@arm.com, peterz@infradead.org, tglx@linutronix.de Reply-To: mingo@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org, vincent.weaver@maine.edu, will.deacon@arm.com, peterz@infradead.org, tglx@linutronix.de In-Reply-To: <1385560479-11014-1-git-send-email-will.deacon@arm.com> References: <1385560479-11014-1-git-send-email-will.deacon@arm.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:perf/core] perf: Fix PERF_EVENT_IOC_PERIOD to force-reset the period Git-Commit-ID: bad7192b842c83e580747ca57104dd51fe08c223 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 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.1 (terminus.zytor.com [127.0.0.1]); Wed, 18 Dec 2013 02:32:36 -0800 (PST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: bad7192b842c83e580747ca57104dd51fe08c223 Gitweb: http://git.kernel.org/tip/bad7192b842c83e580747ca57104dd51fe08c223 Author: Peter Zijlstra AuthorDate: Wed, 27 Nov 2013 13:54:38 +0000 Committer: Ingo Molnar CommitDate: Tue, 17 Dec 2013 15:21:33 +0100 perf: Fix PERF_EVENT_IOC_PERIOD to force-reset the period Vince Weaver reports that, on all architectures apart from ARM, PERF_EVENT_IOC_PERIOD doesn't actually update the period until the next event fires. This is counter-intuitive behaviour and is better dealt with in the core code. This patch ensures that the period is forcefully reset when dealing with such a request in the core code. A subsequent patch removes the equivalent hack from the ARM back-end. Reported-by: Vince Weaver Signed-off-by: Peter Zijlstra Signed-off-by: Will Deacon Link: http://lkml.kernel.org/r/1385560479-11014-1-git-send-email-will.deacon@arm.com Signed-off-by: Ingo Molnar --- kernel/events/core.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index 403b781..89d34f9 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -3527,7 +3527,7 @@ static void perf_event_for_each(struct perf_event *event, static int perf_event_period(struct perf_event *event, u64 __user *arg) { struct perf_event_context *ctx = event->ctx; - int ret = 0; + int ret = 0, active; u64 value; if (!is_sampling_event(event)) @@ -3551,6 +3551,20 @@ static int perf_event_period(struct perf_event *event, u64 __user *arg) event->attr.sample_period = value; event->hw.sample_period = value; } + + active = (event->state == PERF_EVENT_STATE_ACTIVE); + if (active) { + perf_pmu_disable(ctx->pmu); + event->pmu->stop(event, PERF_EF_UPDATE); + } + + local64_set(&event->hw.period_left, 0); + + if (active) { + event->pmu->start(event, PERF_EF_RELOAD); + perf_pmu_enable(ctx->pmu); + } + unlock: raw_spin_unlock_irq(&ctx->lock);