From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S267230AbUHaTcW (ORCPT ); Tue, 31 Aug 2004 15:32:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S267263AbUHaTbz (ORCPT ); Tue, 31 Aug 2004 15:31:55 -0400 Received: from mx2.elte.hu ([157.181.151.9]:47066 "EHLO mx2.elte.hu") by vger.kernel.org with ESMTP id S269031AbUHaT2v (ORCPT ); Tue, 31 Aug 2004 15:28:51 -0400 Date: Tue, 31 Aug 2004 21:30:29 +0200 From: Ingo Molnar To: Thomas Charbonnel Cc: Lee Revell , Daniel Schmitt , "K.R. Foley" , Felipe Alfaro Solana , linux-kernel , Mark_H_Johnson@raytheon.com Subject: Re: [patch] voluntary-preempt-2.6.9-rc1-bk4-Q5 Message-ID: <20040831193029.GA29912@elte.hu> References: <1093727453.8611.71.camel@krustophenia.net> <20040828211334.GA32009@elte.hu> <1093727817.860.1.camel@krustophenia.net> <1093737080.1385.2.camel@krustophenia.net> <1093746912.1312.4.camel@krustophenia.net> <20040829054339.GA16673@elte.hu> <20040830090608.GA25443@elte.hu> <1093875939.5534.9.camel@localhost> <20040830180011.GA7419@elte.hu> <1093980227.8005.14.camel@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1093980227.8005.14.camel@localhost> User-Agent: Mutt/1.4.1i X-ELTE-SpamVersion: MailScanner 4.31.6-itk1 (ELTE 1.2) SpamAssassin 2.63 ClamAV 0.73 X-ELTE-VirusStatus: clean X-ELTE-SpamCheck: no X-ELTE-SpamCheck-Details: score=-4.9, required 5.9, autolearn=not spam, BAYES_00 -4.90 X-ELTE-SpamLevel: X-ELTE-SpamScore: -4 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org * Thomas Charbonnel wrote: > As you can see ~1ms was probably an accident, and the latency does not > always come from do_timer. The constant is do_IRQ interrupting the > idle thread. (do you have any sort of powersaving mode (ACPI/APM) enabled? If yes, could you try to tune it down as much as possible - disable any powersaving option in the BIOS and in the .config - kill apmd, etc.) but i dont think it's powersaving - why would such an overhead show up in those functions. The only common thing seems to be that both mark_offset_tsc() and mask_and_ack_8259A() does port IO, which is slow - but still it shouldnt take ~0.5 msecs! Ingo