From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761367AbZAQMAg (ORCPT ); Sat, 17 Jan 2009 07:00:36 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756434AbZAQMAZ (ORCPT ); Sat, 17 Jan 2009 07:00:25 -0500 Received: from casper.infradead.org ([85.118.1.10]:44876 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756247AbZAQMAY (ORCPT ); Sat, 17 Jan 2009 07:00:24 -0500 Subject: Re: [git pull] scheduler fixes From: Peter Zijlstra To: Mike Galbraith Cc: Andrew Morton , Ingo Molnar , Linus Torvalds , LKML In-Reply-To: <1232188484.6813.85.camel@marge.simson.net> References: <20090111144305.GA7154@elte.hu> <20090114121521.197dfc5e.akpm@linux-foundation.org> <1231964647.14825.59.camel@laptop> <20090116204049.f4d6ef1c.akpm@linux-foundation.org> <1232173776.7073.21.camel@marge.simson.net> <1232186054.6813.48.camel@marge.simson.net> <1232186877.14073.59.camel@laptop> <1232188484.6813.85.camel@marge.simson.net> Content-Type: text/plain Date: Sat, 17 Jan 2009 13:00:17 +0100 Message-Id: <1232193617.14073.67.camel@laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.24.2 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 2009-01-17 at 11:34 +0100, Mike Galbraith wrote: > > Right, how about we flip the 'initial' case in place_entity() for ! > > nr_exclusive wakeups. > > Wouldn't that be more drastic than sleep denial? Strictly speaking that DEBIT thing is valid for each wakeup, IIRC we restricted it to clone() only because that was where we could actually observe these latency spikes using a fork-bomb. This reduces the latency hits to around 400ms, which is about right for the given load. --- diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index f34cf42..d344605 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -671,7 +671,8 @@ place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int initial) * little, place the new task so that it fits in the slot that * stays open at the end. */ - if (initial && sched_feat(START_DEBIT)) + if ((initial && sched_feat(START_DEBIT)) || + (!initial && sched_feat(WAKER_DEBIT))) vruntime += sched_vslice(cfs_rq, se); if (!initial) { diff --git a/kernel/sched_features.h b/kernel/sched_features.h index 4569bfa..b5fddf0 100644 --- a/kernel/sched_features.h +++ b/kernel/sched_features.h @@ -1,4 +1,4 @@ -SCHED_FEAT(NEW_FAIR_SLEEPERS, 1) +SCHED_FEAT(NEW_FAIR_SLEEPERS, 0) SCHED_FEAT(NORMALIZED_SLEEPER, 0) SCHED_FEAT(ADAPTIVE_GRAN, 1) SCHED_FEAT(WAKEUP_PREEMPT, 1) @@ -15,3 +15,4 @@ SCHED_FEAT(ASYM_EFF_LOAD, 1) SCHED_FEAT(WAKEUP_OVERLAP, 0) SCHED_FEAT(LAST_BUDDY, 1) SCHED_FEAT(OWNER_SPIN, 1) +SCHED_FEAT(WAKER_DEBIT, 1)