Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262031AbTEHTWd (ORCPT ); Thu, 8 May 2003 15:22:33 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262037AbTEHTWd (ORCPT ); Thu, 8 May 2003 15:22:33 -0400 Received: from h-68-165-86-241.DLLATX37.covad.net ([68.165.86.241]:12602 "EHLO sol.microgate.com") by vger.kernel.org with ESMTP id S262031AbTEHTWc (ORCPT ); Thu, 8 May 2003 15:22:32 -0400 Subject: Re: 2.5.69 Interrupt Latency From: Paul Fulghum To: Andrew Morton Cc: "linux-kernel@vger.kernel.org" In-Reply-To: <20030508122205.7b4b8a02.akpm@digeo.com> References: <1052323940.2360.7.camel@diemos> <1052336482.2020.8.camel@diemos> <20030507152856.2a71601d.akpm@digeo.com> <1052402187.1995.13.camel@diemos> <20030508122205.7b4b8a02.akpm@digeo.com> Content-Type: text/plain Organization: Message-Id: <1052422517.2024.6.camel@diemos> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.2.2 (1.2.2-4) Date: 08 May 2003 14:35:18 -0500 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1499 Lines: 46 On Thu, 2003-05-08 at 14:22, Andrew Morton wrote: > Paul Fulghum wrote: > > > > On Wed, 2003-05-07 at 17:28, Andrew Morton wrote: > > > Paul Fulghum wrote: > > > > > > > > 2.5.69 > > > > Latency 100-110usec (5x increase) > > > > Spikes from 5-10 milliseconds > > > > > > I'm going to try your suggestion of doing a stack dump > > when the driver encounters the large spikes in IRQ latency, > > to determine if something is leaving interrupts disabled. > > I wasn't very informative, alas. Yeah, I've been reading through the 2.5.69 patch again and could not really see anything that related to the stack dump. > > That will not address the fact that the minimum > > latency has jumped from 20usec (2.4.20 - 2.5.68) to 100usec > > (2.5.69). This may actually be two separate problems > > introduced with 2.5.69 > > Can you pinpoint a kernel version at which it started to happen? Exactly with 2.5.69 2.5.68 works fine as do earlier versions back to 2.4.20-8 (earliest tested for this problem). All these versions have very consistant latencies as described above. The problem definately started with the 2.5.69 -- Paul Fulghum, paulkf@microgate.com Microgate Corporation, http://www.microgate.com - 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/