From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265591AbTGOI7G (ORCPT ); Tue, 15 Jul 2003 04:59:06 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265764AbTGOI7G (ORCPT ); Tue, 15 Jul 2003 04:59:06 -0400 Received: from 69-55-72-150.ppp.netsville.net ([69.55.72.150]:39379 "EHLO tiny.suse.com") by vger.kernel.org with ESMTP id S265591AbTGOI7B (ORCPT ); Tue, 15 Jul 2003 04:59:01 -0400 Subject: Re: RFC on io-stalls patch From: Chris Mason To: Jens Axboe Cc: Andrea Arcangeli , Andrew Morton , marcelo@conectiva.com.br, linux-kernel@vger.kernel.org, akpm@digeo.com In-Reply-To: <20030715082850.GH833@suse.de> References: <20030714202434.GS16313@dualathlon.random> <1058214881.13313.291.camel@tiny.suse.com> <20030714224528.GU16313@dualathlon.random> <1058229360.13317.364.camel@tiny.suse.com> <20030714175238.3eaddd9a.akpm@osdl.org> <20030715020706.GC16313@dualathlon.random> <20030715054551.GD833@suse.de> <20030715060101.GB30537@dualathlon.random> <20030715060857.GG833@suse.de> <20030715070314.GD30537@dualathlon.random> <20030715082850.GH833@suse.de> Content-Type: text/plain Organization: Message-Id: <1058260347.4012.11.camel@tiny.suse.com> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.2.2 Date: 15 Jul 2003 05:12:28 -0400 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2003-07-15 at 04:28, Jens Axboe wrote: > Definitely, because prepare to be a bit disappointed. Here are scores > that include 2.4.21 as well: > io_load: > Kernel [runs] Time CPU% Loads LCPU% Ratio > 2.4.21 3 543 49.7 100.4 19.0 4.08 > 2.4.22-pre5 3 637 42.5 120.2 18.5 4.75 > 2.4.22-pre5-axboe 3 540 50.0 103.0 18.1 4.06 Huh, this is completely different than io_load on my box (2P scsi, ext3, data=writeback) io_load: Kernel [runs] Time CPU% Loads LCPU% Ratio 2.4.21 3 520 52.5 27.8 15.2 3.80 2.4.22-pre5 3 394 69.0 21.5 15.4 2.90 2.4.22-sync 3 321 84.7 16.2 15.8 2.36 Where 2.4.22-sync was the variant I posted yesterday. I don't really see how 2.4.21 can get numbers as good as 2.4.22-pre5 on the io_load test, the read starvation with a big streaming io is horrible. The data=writeback is changing the workload significantly, I used it because I didn't want the data=ordered code to flush all dirty buffers every 5 seconds. I would expect ext3 data=ordered to be pretty starvation prone in 2.4.21 as well though. BTW, the contest run times vary pretty wildy. My 3 compiles with io_load running on 2.4.21 were 603s, 443s and 515s. This doesn't make the average of the 3 numbers invalid, but we need a more stable metric. -chris