From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755359AbaKPJvL (ORCPT ); Sun, 16 Nov 2014 04:51:11 -0500 Received: from terminus.zytor.com ([198.137.202.10]:34408 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755309AbaKPJvJ (ORCPT ); Sun, 16 Nov 2014 04:51:09 -0500 Date: Sun, 16 Nov 2014 01:50:31 -0800 From: tip-bot for Peter Zijlstra Message-ID: Cc: linux-kernel@vger.kernel.org, peterz@infradead.org, cl@linux.com, tglx@linutronix.de, fweisbec@gmail.com, mingo@kernel.org, hpa@zytor.com, kosaki.motohiro@jp.fujitsu.com, riel@redhat.com, oleg@redhat.com, sgruszka@redhat.com, tj@kernel.org, torvalds@linux-foundation.org Reply-To: linux-kernel@vger.kernel.org, peterz@infradead.org, cl@linux.com, tglx@linutronix.de, fweisbec@gmail.com, mingo@kernel.org, oleg@redhat.com, riel@redhat.com, kosaki.motohiro@jp.fujitsu.com, hpa@zytor.com, torvalds@linux-foundation.org, sgruszka@redhat.com, tj@kernel.org In-Reply-To: <20141112113737.GI10476@twins.programming.kicks-ass.net> References: <20141112113737.GI10476@twins.programming.kicks-ass.net> To: linux-tip-commits@vger.kernel.org Subject: [tip:sched/urgent] sched/cputime: Fix cpu_timer_sample_group() double accounting Git-Commit-ID: 23cfa361f3e54a3e184a5e126bbbdd95f984881a 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: 23cfa361f3e54a3e184a5e126bbbdd95f984881a Gitweb: http://git.kernel.org/tip/23cfa361f3e54a3e184a5e126bbbdd95f984881a Author: Peter Zijlstra AuthorDate: Wed, 12 Nov 2014 12:37:37 +0100 Committer: Ingo Molnar CommitDate: Sun, 16 Nov 2014 10:04:18 +0100 sched/cputime: Fix cpu_timer_sample_group() double accounting While looking over the cpu-timer code I found that we appear to add the delta for the calling task twice, through: cpu_timer_sample_group() thread_group_cputimer() thread_group_cputime() times->sum_exec_runtime += task_sched_runtime(); *sample = cputime.sum_exec_runtime + task_delta_exec(); Which would make the sample run ahead, making the sleep short. Signed-off-by: Peter Zijlstra (Intel) Cc: KOSAKI Motohiro Cc: Oleg Nesterov Cc: Stanislaw Gruszka Cc: Christoph Lameter Cc: Frederic Weisbecker Cc: Linus Torvalds Cc: Rik van Riel Cc: Tejun Heo Link: http://lkml.kernel.org/r/20141112113737.GI10476@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar --- include/linux/kernel_stat.h | 5 ----- kernel/sched/core.c | 13 ------------- kernel/time/posix-cpu-timers.c | 2 +- 3 files changed, 1 insertion(+), 19 deletions(-) diff --git a/include/linux/kernel_stat.h b/include/linux/kernel_stat.h index 8422b4e..b9376cd 100644 --- a/include/linux/kernel_stat.h +++ b/include/linux/kernel_stat.h @@ -77,11 +77,6 @@ static inline unsigned int kstat_cpu_irqs_sum(unsigned int cpu) return kstat_cpu(cpu).irqs_sum; } -/* - * Lock/unlock the current runqueue - to extract task statistics: - */ -extern unsigned long long task_delta_exec(struct task_struct *); - extern void account_user_time(struct task_struct *, cputime_t, cputime_t); extern void account_system_time(struct task_struct *, int, cputime_t, cputime_t); extern void account_steal_time(cputime_t); diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 5f12ca6..797a6c8 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2499,19 +2499,6 @@ static u64 do_task_delta_exec(struct task_struct *p, struct rq *rq) return ns; } -unsigned long long task_delta_exec(struct task_struct *p) -{ - unsigned long flags; - struct rq *rq; - u64 ns = 0; - - rq = task_rq_lock(p, &flags); - ns = do_task_delta_exec(p, rq); - task_rq_unlock(rq, p, &flags); - - return ns; -} - /* * Return accounted runtime for the task. * In case the task is currently running, return the runtime plus current's diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c index 492b986..a16b678 100644 --- a/kernel/time/posix-cpu-timers.c +++ b/kernel/time/posix-cpu-timers.c @@ -553,7 +553,7 @@ static int cpu_timer_sample_group(const clockid_t which_clock, *sample = cputime_to_expires(cputime.utime); break; case CPUCLOCK_SCHED: - *sample = cputime.sum_exec_runtime + task_delta_exec(p); + *sample = cputime.sum_exec_runtime; break; } return 0;