Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755765AbXH0Or4 (ORCPT ); Mon, 27 Aug 2007 10:47:56 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754945AbXH0Orr (ORCPT ); Mon, 27 Aug 2007 10:47:47 -0400 Received: from [212.12.190.28] ([212.12.190.28]:32870 "EHLO raad.intranet" rhost-flags-FAIL-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1756666AbXH0Orq (ORCPT ); Mon, 27 Aug 2007 10:47:46 -0400 From: Al Boldi To: Ingo Molnar Subject: Re: CFS review Date: Mon, 27 Aug 2007 17:46:47 +0300 User-Agent: KMail/1.5 Cc: Peter Zijlstra , Mike Galbraith , Andrew Morton , Linus Torvalds , linux-kernel@vger.kernel.org References: <200708111344.42934.a1426z@gawab.com> <200708270706.41565.a1426z@gawab.com> <20070827105317.GA15003@elte.hu> In-Reply-To: <20070827105317.GA15003@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200708271746.47685.a1426z@gawab.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1371 Lines: 42 Ingo Molnar wrote: > * Al Boldi wrote: > > > could you send the exact patch that shows what you did? > > > > On 2.6.22.5-v20.3 (not v20.4): > > > > 340- curr->delta_exec += delta_exec; > > 341- > > 342- if (unlikely(curr->delta_exec > sysctl_sched_stat_granularity)) > > { 343:// __update_curr(cfs_rq, curr); > > 344- curr->delta_exec = 0; > > 345- } > > 346- curr->exec_start = rq_of(cfs_rq)->clock; > > ouch - this produces a really broken scheduler - with this we dont do > any run-time accounting (!). Of course it's broken, and it's not meant as a fix, but this change allows you to see the amount of overhead as well as any miscalculations __update_curr incurs. In terms of overhead, __update_curr incurs ~3x slowdown, and in terms of run-time accounting it exhibits a ~10sec task-startup miscalculation. > Could you try the patch below instead, does this make 3x glxgears smooth > again? (if yes, could you send me your Signed-off-by line as well.) The task-startup stalling is still there for ~10sec. Can you see the problem on your machine? Thanks! -- Al - 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/