From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S267568AbUHaUsh (ORCPT ); Tue, 31 Aug 2004 16:48:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S267591AbUHaUqX (ORCPT ); Tue, 31 Aug 2004 16:46:23 -0400 Received: from mx1.elte.hu ([157.181.1.137]:41436 "EHLO mx1.elte.hu") by vger.kernel.org with ESMTP id S268800AbUHaUhT (ORCPT ); Tue, 31 Aug 2004 16:37:19 -0400 Date: Tue, 31 Aug 2004 22:37:39 +0200 From: Ingo Molnar To: Mark_H_Johnson@raytheon.com Cc: "K.R. Foley" , linux-kernel , Felipe Alfaro Solana , Daniel Schmitt , Lee Revell Subject: Re: [patch] voluntary-preempt-2.6.9-rc1-bk4-Q5 Message-ID: <20040831203739.GA2356@elte.hu> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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 * Mark_H_Johnson@raytheon.com wrote: > >since the latency tracer does not trigger, we need a modified tracer to > >find out what's happening during such long delays. I've attached the > >'user-latency-tracer' patch ontop of -Q5, which is a modification of the > >latency tracer. > Grr. I should have checked before I built with this patch. With this in > I now get the > kernel: Could not allocate 4 bytes percpu data > messages again. Need to increase that data area so > #define PERCPU_ENOUGH_ROOM 196608 > or something similar (should leave about 50K free for modules). ok, i've upped that value in my tree too. > I will rebuild with this change plus the latest of the others. since your traces do show those 'mystic' latency incidents causing 200-500 usec overhead in few-instructions code paths, perhaps the 1 msec jitter you are seeing could a consequence of this too. So perhaps it would make sense to first try disabling IDE DMA, to see whether this has any effect on the magic latencies. Ingo