From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753017AbcHBKia (ORCPT ); Tue, 2 Aug 2016 06:38:30 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:51435 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751276AbcHBKiV (ORCPT ); Tue, 2 Aug 2016 06:38:21 -0400 Date: Tue, 2 Aug 2016 12:37:29 +0200 From: Peter Zijlstra To: Giovanni Gherdovich Cc: Ingo Molnar , Mike Galbraith , Stanislaw Gruszka , linux-kernel@vger.kernel.org, Mel Gorman Subject: Re: [PATCH] sched/cputime: Mitigate performance regression in times()/clock_gettime() Message-ID: <20160802103729.GG6862@twins.programming.kicks-ass.net> References: <1469542034-9542-1-git-send-email-ggherdovich@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1469542034-9542-1-git-send-email-ggherdovich@suse.cz> User-Agent: Mutt/1.5.23.1 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 26, 2016 at 04:07:14PM +0200, Giovanni Gherdovich wrote: > Signed-off-by: Mike Galbraith > Signed-off-by: Giovanni Gherdovich SoB chain is borken. Either Mike wrote the patch in which case you're missing a From: Mike header someplace, or you wrote it and Mike needs to be a Ack/Reviewed or somesuch. > --- > kernel/sched/core.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index 51d7105..0ef1e69 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -2998,6 +2998,10 @@ unsigned long long task_sched_runtime(struct task_struct *p) > * thread, breaking clock_gettime(). > */ > if (task_current(rq, p) && task_on_rq_queued(p)) { > +#if defined(CONFIG_FAIR_GROUP_SCHED) This here wants a comment on why we're doing this. Because I'm sure that if someone were to read this code in a few weeks they'd go WTF!? Also, is there a possibility of manual CSE we should do? > + prefetch((&p->se)->cfs_rq->curr); > + prefetch(&(&p->se)->cfs_rq->curr->exec_start); > +#endif > update_rq_clock(rq); > p->sched_class->update_curr(rq); > } > -- > 2.6.6 >