Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754112AbWKGIZ3 (ORCPT ); Tue, 7 Nov 2006 03:25:29 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754113AbWKGIZ3 (ORCPT ); Tue, 7 Nov 2006 03:25:29 -0500 Received: from mx2.mail.elte.hu ([157.181.151.9]:11397 "EHLO mx2.mail.elte.hu") by vger.kernel.org with ESMTP id S1754112AbWKGIZ2 (ORCPT ); Tue, 7 Nov 2006 03:25:28 -0500 Date: Tue, 7 Nov 2006 09:24:35 +0100 From: Ingo Molnar To: Andreas Mohr Cc: Len Brown , Thomas Gleixner , linux-kernel@vger.kernel.org Subject: Re: CONFIG_NO_HZ: missed ticks, stall (keyb IRQ required) [2.6.18-rc4-mm1] Message-ID: <20061107082434.GA13585@elte.hu> References: <20061101140729.GA30005@rhlx01.hs-esslingen.de> <1162830033.4715.201.camel@localhost.localdomain> <20061106205825.GA26755@rhlx01.hs-esslingen.de> <200611070141.16593.len.brown@intel.com> <20061107081839.GA26290@rhlx01.hs-esslingen.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20061107081839.GA26290@rhlx01.hs-esslingen.de> User-Agent: Mutt/1.4.2.2i X-ELTE-SpamScore: -2.8 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.8 required=5.9 tests=ALL_TRUSTED,AWL,BAYES_50 autolearn=no SpamAssassin version=3.0.3 -3.3 ALL_TRUSTED Did not pass through any untrusted hosts 0.5 BAYES_50 BODY: Bayesian spam probability is 40 to 60% [score: 0.5000] -0.0 AWL AWL: From: address is in the auto white-list X-ELTE-VirusStatus: clean Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1153 Lines: 30 * Andreas Mohr wrote: > The results are (waited for values to settle down each time): > > -dyntick4, C1, CONFIG_NO_HZ: > 83.9W KDE idle, 95.2W bash while 1 > -dyntick4, C2 (C1-only hack disabled, kernel rebuilt), CONFIG_NO_HZ off: > 84.4W KDE idle, 95.4W bash while 1 > -dyntick4, acpi=off (i.e. APM active), -dynticks: > 85.5W KDE idle, 95.5W bash while 1 > > Bet you didn't see this coming... interesting that there's any savings from dynticks in this workload. When the CPU is busy then dynticks generates the usual HZ scheduler tick. could you try the same measurement with a completely idle system too? That is where dynticks has its true effects: longer idle intervals. (but even on an idle system dynticks might not make a difference unless the hardware can utilize the much larger and more predictable idle times that dynticks offers.) 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/