From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753437AbZELNe3 (ORCPT ); Tue, 12 May 2009 09:34:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752053AbZELNeT (ORCPT ); Tue, 12 May 2009 09:34:19 -0400 Received: from hera.kernel.org ([140.211.167.34]:54286 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751989AbZELNeS (ORCPT ); Tue, 12 May 2009 09:34:18 -0400 Date: Tue, 12 May 2009 13:33:31 GMT From: tip-bot for Paul Mackerras To: linux-tip-commits@vger.kernel.org Cc: linux-kernel@vger.kernel.org, paulus@samba.org, hpa@zytor.com, mingo@redhat.com, a.p.zijlstra@chello.nl, tglx@linutronix.de, cjashfor@linux.vnet.ibm.com, mingo@elte.hu Reply-To: mingo@redhat.com, hpa@zytor.com, paulus@samba.org, linux-kernel@vger.kernel.org, a.p.zijlstra@chello.nl, tglx@linutronix.de, cjashfor@linux.vnet.ibm.com, mingo@elte.hu In-Reply-To: <18953.25733.53359.147452@cargo.ozlabs.ibm.com> References: <18953.25733.53359.147452@cargo.ozlabs.ibm.com> Subject: [tip:perfcounters/core] perf_counter: call hw_perf_save_disable/restore around group_sched_in Message-ID: Git-Commit-ID: e758a33d6fc5b9d6a3ae489863d04fcecad8120b 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]); Tue, 12 May 2009 13:33:33 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: e758a33d6fc5b9d6a3ae489863d04fcecad8120b Gitweb: http://git.kernel.org/tip/e758a33d6fc5b9d6a3ae489863d04fcecad8120b Author: Paul Mackerras AuthorDate: Tue, 12 May 2009 21:59:01 +1000 Committer: Ingo Molnar CommitDate: Tue, 12 May 2009 15:31:06 +0200 perf_counter: call hw_perf_save_disable/restore around group_sched_in I noticed that when enabling a group via the PERF_COUNTER_IOC_ENABLE ioctl on the group leader, the counters weren't enabled and counting immediately on return from the ioctl, but did start counting a little while later (presumably after a context switch). The reason was that __perf_counter_enable calls group_sched_in which calls hw_perf_group_sched_in, which on powerpc assumes that the caller has called hw_perf_save_disable already. Until commit 46d686c6 ("perf_counter: put whole group on when enabling group leader") it was true that all callers of group_sched_in had called hw_perf_save_disable first, and the powerpc hw_perf_group_sched_in relies on that (there isn't an x86 version). This fixes the problem by putting calls to hw_perf_save_disable / hw_perf_restore around the calls to group_sched_in and counter_sched_in in __perf_counter_enable. Having the calls to hw_perf_save_disable/restore around the counter_sched_in call is harmless and makes this call consistent with the other call sites of counter_sched_in, which have all called hw_perf_save_disable first. [ Impact: more precise counter group disable/enable functionality ] Signed-off-by: Paul Mackerras Cc: Peter Zijlstra Cc: Corey Ashford LKML-Reference: <18953.25733.53359.147452@cargo.ozlabs.ibm.com> Signed-off-by: Ingo Molnar --- kernel/perf_counter.c | 19 ++++++++++++------- 1 files changed, 12 insertions(+), 7 deletions(-) diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c index 5ea0240..ff166c1 100644 --- a/kernel/perf_counter.c +++ b/kernel/perf_counter.c @@ -663,6 +663,7 @@ static void __perf_counter_enable(void *info) struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context); struct perf_counter_context *ctx = counter->ctx; struct perf_counter *leader = counter->group_leader; + unsigned long pmuflags; unsigned long flags; int err; @@ -689,14 +690,18 @@ static void __perf_counter_enable(void *info) if (leader != counter && leader->state != PERF_COUNTER_STATE_ACTIVE) goto unlock; - if (!group_can_go_on(counter, cpuctx, 1)) + if (!group_can_go_on(counter, cpuctx, 1)) { err = -EEXIST; - else if (counter == leader) - err = group_sched_in(counter, cpuctx, ctx, - smp_processor_id()); - else - err = counter_sched_in(counter, cpuctx, ctx, - smp_processor_id()); + } else { + pmuflags = hw_perf_save_disable(); + if (counter == leader) + err = group_sched_in(counter, cpuctx, ctx, + smp_processor_id()); + else + err = counter_sched_in(counter, cpuctx, ctx, + smp_processor_id()); + hw_perf_restore(pmuflags); + } if (err) { /*