From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S267026AbTGOJ4T (ORCPT ); Tue, 15 Jul 2003 05:56:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S267064AbTGOJ4T (ORCPT ); Tue, 15 Jul 2003 05:56:19 -0400 Received: from ns.virtualhost.dk ([195.184.98.160]:1763 "EHLO virtualhost.dk") by vger.kernel.org with ESMTP id S267026AbTGOJ4R (ORCPT ); Tue, 15 Jul 2003 05:56:17 -0400 Date: Tue, 15 Jul 2003 12:11:04 +0200 From: Jens Axboe To: Andrea Arcangeli Cc: Chris Mason , Andrew Morton , marcelo@conectiva.com.br, linux-kernel@vger.kernel.org, akpm@digeo.com Subject: Re: RFC on io-stalls patch Message-ID: <20030715101104.GK833@suse.de> References: <20030715020706.GC16313@dualathlon.random> <20030715054551.GD833@suse.de> <20030715060101.GB30537@dualathlon.random> <20030715060857.GG833@suse.de> <20030715070314.GD30537@dualathlon.random> <20030715082850.GH833@suse.de> <1058260347.4012.11.camel@tiny.suse.com> <20030715091730.GI833@suse.de> <20030715091838.GJ833@suse.de> <20030715100357.GI30537@dualathlon.random> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20030715100357.GI30537@dualathlon.random> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 15 2003, Andrea Arcangeli wrote: > On Tue, Jul 15, 2003 at 11:18:38AM +0200, Jens Axboe wrote: > > On Tue, Jul 15 2003, Jens Axboe wrote: > > > > 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. > > > > > > Mine are pretty consistent [1], I'd suspect that it isn't contest but your > > > drive tcq skewing things. But it would be nice to test with other things > > > as well, I just used contest because it was at hand. > > > > Oh and in the same spirit, I'll do the complete runs on an IDE drive as > > well. Sometimes IDE vs SCSI shows the funniest things. > > this is the first suspect IMHO too. Especially given the way that SCSI > releases the requests. 2.4.21 + 2.4.22-pre5 + 2.4.22-pre5-axboe is running/pending on IDE now here. > One more thing: unlike my patch where I forced all drivers to support > elevator-lowlatency (either that or not compile at all), Chris made it > optional when he pushed it into mainline, so now the device driver has > to call blk_queue_throttle_sectors(q, 1) to enable it. Otherwise it'll > run like 2.4.21. Right, but both IDE and SCSI sets it. IDE is still the best to bench io scheduler performance on, though. -- Jens Axboe