From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753161AbZIQUNq (ORCPT ); Thu, 17 Sep 2009 16:13:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752922AbZIQUNo (ORCPT ); Thu, 17 Sep 2009 16:13:44 -0400 Received: from hera.kernel.org ([140.211.167.34]:36856 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752249AbZIQUNl (ORCPT ); Thu, 17 Sep 2009 16:13:41 -0400 Date: Thu, 17 Sep 2009 20:12:54 GMT From: tip-bot for Peter Zijlstra Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@redhat.com, a.p.zijlstra@chello.nl, tglx@linutronix.de, mingo@elte.hu Reply-To: mingo@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, a.p.zijlstra@chello.nl, tglx@linutronix.de, mingo@elte.hu In-Reply-To: References: To: linux-tip-commits@vger.kernel.org Subject: [tip:perfcounters/core] perf_counter: Do not throttle single swcounter events Message-ID: Git-Commit-ID: 850bc73ffcc99cddfb52bc23217c60810c508853 X-Mailer: tip-git-log-daemon MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.0 (hera.kernel.org [127.0.0.1]); Thu, 17 Sep 2009 20:13:07 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 850bc73ffcc99cddfb52bc23217c60810c508853 Gitweb: http://git.kernel.org/tip/850bc73ffcc99cddfb52bc23217c60810c508853 Author: Peter Zijlstra AuthorDate: Thu, 17 Sep 2009 18:47:11 +0200 Committer: Ingo Molnar CommitDate: Thu, 17 Sep 2009 22:08:25 +0200 perf_counter: Do not throttle single swcounter events We can have swcounter events that contribute more than a single count per event, when used with a non-zero period, those can generate multiple events, which is when we need throttling. However, swcounter that contribute only a single count per event can only come as fast as we can run code, hence don't throttle them. Signed-off-by: Peter Zijlstra LKML-Reference: Signed-off-by: Ingo Molnar --- kernel/perf_counter.c | 17 +++++++++++++---- 1 files changed, 13 insertions(+), 4 deletions(-) diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c index 667ab25..fe0d1ad 100644 --- a/kernel/perf_counter.c +++ b/kernel/perf_counter.c @@ -3494,14 +3494,15 @@ static void perf_log_throttle(struct perf_counter *counter, int enable) * Generic counter overflow handling, sampling. */ -int perf_counter_overflow(struct perf_counter *counter, int nmi, - struct perf_sample_data *data) +static int __perf_counter_overflow(struct perf_counter *counter, int nmi, + int throttle, struct perf_sample_data *data) { int events = atomic_read(&counter->event_limit); - int throttle = counter->pmu->unthrottle != NULL; struct hw_perf_counter *hwc = &counter->hw; int ret = 0; + throttle = (throttle && counter->pmu->unthrottle != NULL); + if (!throttle) { hwc->interrupts++; } else { @@ -3554,6 +3555,12 @@ int perf_counter_overflow(struct perf_counter *counter, int nmi, return ret; } +int perf_counter_overflow(struct perf_counter *counter, int nmi, + struct perf_sample_data *data) +{ + return __perf_counter_overflow(counter, nmi, 1, data); +} + /* * Generic software counter infrastructure */ @@ -3592,6 +3599,7 @@ static void perf_swcounter_overflow(struct perf_counter *counter, int nmi, struct perf_sample_data *data) { struct hw_perf_counter *hwc = &counter->hw; + int throttle = 0; u64 overflow; data->period = counter->hw.last_period; @@ -3601,13 +3609,14 @@ static void perf_swcounter_overflow(struct perf_counter *counter, return; for (; overflow; overflow--) { - if (perf_counter_overflow(counter, nmi, data)) { + if (__perf_counter_overflow(counter, nmi, throttle, data)) { /* * We inhibit the overflow from happening when * hwc->interrupts == MAX_INTERRUPTS. */ break; } + throttle = 0; } }