Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932781AbYAaK3r (ORCPT ); Thu, 31 Jan 2008 05:29:47 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1762490AbYAaK3h (ORCPT ); Thu, 31 Jan 2008 05:29:37 -0500 Received: from mx3.mail.elte.hu ([157.181.1.138]:40259 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1762678AbYAaK3f (ORCPT ); Thu, 31 Jan 2008 05:29:35 -0500 Date: Thu, 31 Jan 2008 11:29:19 +0100 From: Ingo Molnar To: Lukas Hejtmanek Cc: mingo@redhat.com, linux-kernel@vger.kernel.org, Peter Zijlstra Subject: Re: 2.6.24-git4+ regression Message-ID: <20080131102919.GC27157@elte.hu> References: <20080130135609.GA5100@ics.muni.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080130135609.GA5100@ics.muni.cz> User-Agent: Mutt/1.5.17 (2007-11-01) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1697 Lines: 50 * Lukas Hejtmanek wrote: > I noticed short thread in LKM regarding "sched: add vslice" causes > horrible interactivity under load. > > I can see similar behavior. If I stress both CPU cores, even typing on > keyboard suffers from huge latencies, I can see letters appearing with > delay (typing into xterm). No swap is used at all, having 1GB free > RAM. > > I noticed this bad behavior with 2.6.24-git[46], 2.6.24-rc8-git was > OK. if you apply the current sched-fixes (rollup patch below), does it get any better? Ingo Index: linux/kernel/sched_fair.c =================================================================== --- linux.orig/kernel/sched_fair.c +++ linux/kernel/sched_fair.c @@ -520,7 +520,7 @@ place_entity(struct cfs_rq *cfs_rq, stru if (!initial) { /* sleeps upto a single latency don't count. */ - if (sched_feat(NEW_FAIR_SLEEPERS) && entity_is_task(se)) + if (sched_feat(NEW_FAIR_SLEEPERS)) vruntime -= sysctl_sched_latency; /* ensure we never gain time by being placed backwards. */ @@ -1106,7 +1106,11 @@ static void check_preempt_wakeup(struct } gran = sysctl_sched_wakeup_granularity; - if (unlikely(se->load.weight != NICE_0_LOAD)) + /* + * More easily preempt - nice tasks, while not making + * it harder for + nice tasks. + */ + if (unlikely(se->load.weight > NICE_0_LOAD)) gran = calc_delta_fair(gran, &se->load); if (pse->vruntime + gran < se->vruntime) -- 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/