From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262561AbTDHXMJ (for ); Tue, 8 Apr 2003 19:12:09 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262563AbTDHXMJ (for ); Tue, 8 Apr 2003 19:12:09 -0400 Received: from [12.47.58.221] ([12.47.58.221]:31211 "EHLO pao-ex01.pao.digeo.com") by vger.kernel.org with ESMTP id S262561AbTDHXMI (for ); Tue, 8 Apr 2003 19:12:08 -0400 Date: Tue, 8 Apr 2003 15:22:15 -0700 From: Andrew Morton To: Larry McVoy Cc: linux-kernel@vger.kernel.org, Rick Lindsley Subject: Re: 2.5 io statistics? Message-Id: <20030408152215.00b7beca.akpm@digeo.com> In-Reply-To: <20030408155858.GB27912@work.bitmover.com> References: <20030408155858.GB27912@work.bitmover.com> X-Mailer: Sylpheed version 0.8.10 (GTK+ 1.2.10; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 08 Apr 2003 23:23:38.0707 (UTC) FILETIME=[E27FDA30:01C2FE25] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Larry McVoy wrote: > > Is there a writeup of the changes anywhere? I'd like to port cstat to 2.5. > Cstat is sort of a netstat/vmstat combo: > > load free cach swap pgin pgou dk0 dk1 dk2 dk3 ipkt opkt int ctx usr sys idl > 0.00 19M 562M 48M 4.0K 12K 0 0 0 0 137 25 267 83 0 0 100 > 0.00 18M 563M 48M 0 12K 0 0 0 0 133 22 258 77 0 1 99 It's currently undergoing a bit of change. In 2.5.67 all IO activity is monitored by opening and reading /sys/block/hda/stat. This certainly doesn't scale when you have thousands of disks, so there's a patch in -mm which performs runtime aggregation of global stats and exposes that via /proc/diskstats. So if you want to monitor the "global" IO activity, you don't need to open all those sysfs files. I don't know if the aggregate disk stats patch is ready to go yet. I'm awaiting testing results, conversion of userspace tools, etc. I just plonked it in there and haven't heard anything since. As far as I know, neither the format of the sysfs file nor the format of /proc/diskstats is documented anywhere. Perhaps Rick can prepare a description for inclusion under Dcumentation/ somewhere?