Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932153AbWEWJqX (ORCPT ); Tue, 23 May 2006 05:46:23 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932159AbWEWJqX (ORCPT ); Tue, 23 May 2006 05:46:23 -0400 Received: from ns.virtualhost.dk ([195.184.98.160]:46120 "EHLO virtualhost.dk") by vger.kernel.org with ESMTP id S932153AbWEWJqW (ORCPT ); Tue, 23 May 2006 05:46:22 -0400 Date: Tue, 23 May 2006 11:47:48 +0200 From: Jens Axboe To: Martin Devera Cc: linux-kernel@vger.kernel.org Subject: Re: wrong in_flight diskstat in 2.6.16.1 Message-ID: <20060523094748.GR26261@suse.de> References: <4472CD62.5060906@cdi.cz> <20060523092324.GO26261@suse.de> <4472D651.5010206@cdi.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4472D651.5010206@cdi.cz> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1623 Lines: 52 On Tue, May 23 2006, Martin Devera wrote: > Jens Axboe wrote: > >On Tue, May 23 2006, Martin Devera wrote: > >>Hello, > >> > >>I see weird output from /sys/block/sd{a,b}/stat on our AMD64-X2 smp > >>machine with HT1000 (Broadcom) SATA with 2 WD 250GB HDDs in MD raid1. AS > >>scheduler was used, change to noop didn't change anything. It is vanilla > >>2.6.16.1 and here are absolute values in hex and one second differences > >>below: > >> > >>132CDF 56D62 61753C0 6966BC 165A8EB 5FF5B6C 3B32D6C0 1110594C FFCA89A4 > >>FEE85878 49FF74E4 > >>132CDF 56D62 61753C0 6966BC 165A8EF 5FF5B6C 3B32D6E0 111059D0 FFCA89A1 > >>FEE85C60 79291244 > >> 0: 0 > >> 1: 0 > >> 2: 0 > >> 3: 0 > >> 4: 4 > >> 5: 0 > >> 6: 32 > >> 7: 132 > >> 8: -3 > >> 9: 1000 > >>10: 791256416 > >> > >>As you can see in_flight is constantly negative and it is DECREASING > >>slowly all the time. > >>I can't find any reason for it :-\ > > > >Are you using io barriers? > > > >[PATCH] blk: fix gendisk->in_flight accounting during barrier sequence > > I don't think so, I just used > mount / -o remount,barrier=0 > to make it sure and it keeps decrementing. I'll however apply the patch > (and others up to 2.6.16.18) at night (I'm not allowed to restart the > machine just now). Ah, but you are using md, which uses barriers for superblock updates. So the patch will likely help you. -- Jens Axboe - 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/