Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934345AbXHYXPs (ORCPT ); Sat, 25 Aug 2007 19:15:48 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752897AbXHYXPj (ORCPT ); Sat, 25 Aug 2007 19:15:39 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:52529 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752454AbXHYXPi (ORCPT ); Sat, 25 Aug 2007 19:15:38 -0400 Date: Sun, 26 Aug 2007 01:15:26 +0200 From: Ingo Molnar To: Al Boldi Cc: Peter Zijlstra , Mike Galbraith , Andrew Morton , Linus Torvalds , linux-kernel@vger.kernel.org Subject: Re: CFS review Message-ID: <20070825231525.GA334@elte.hu> References: <200708111344.42934.a1426z@gawab.com> <200708220127.30698.a1426z@gawab.com> <20070824134510.GA21382@elte.hu> <200708260127.32238.a1426z@gawab.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200708260127.32238.a1426z@gawab.com> User-Agent: Mutt/1.5.14 (2007-02-12) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: 1.0 X-ELTE-SpamLevel: s X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=1.0 required=5.9 tests=BAYES_50 autolearn=no SpamAssassin version=3.0.3 1.0 BAYES_50 BODY: Bayesian spam probability is 40 to 60% [score: 0.4755] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1403 Lines: 43 * Al Boldi wrote: > > ok. I think i might finally have found the bug causing this. Could > > you try the fix below, does your webserver thread-startup test work > > any better? > > It seems to help somewhat, but the problem is still visible. Even > v20.3 on 2.6.22.5 didn't help. > > It does look related to ia-boosting, so I turned off __update_curr > like Roman mentioned, which had an enormous smoothing effect, but then > nice levels completely break down and lockup the system. you can turn sleeper-fairness off via: echo 28 > /proc/sys/kernel/sched_features another thing to try would be: echo 12 > /proc/sys/kernel/sched_features (that's the new-task penalty turned off.) Another thing to try would be to edit this: if (sysctl_sched_features & SCHED_FEAT_START_DEBIT) p->se.wait_runtime = -(sched_granularity(cfs_rq) / 2); to: if (sysctl_sched_features & SCHED_FEAT_START_DEBIT) p->se.wait_runtime = -(sched_granularity(cfs_rq); and could you also check 20.4 on 2.6.22.5 perhaps, or very latest -git? (Peter has experienced smaller spikes with that.) Ingo - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/