From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S270605AbTGNNAR (ORCPT ); Mon, 14 Jul 2003 09:00:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S270641AbTGNM5r (ORCPT ); Mon, 14 Jul 2003 08:57:47 -0400 Received: from ns.virtualhost.dk ([195.184.98.160]:29860 "EHLO virtualhost.dk") by vger.kernel.org with ESMTP id S270639AbTGNM5b (ORCPT ); Mon, 14 Jul 2003 08:57:31 -0400 Date: Mon, 14 Jul 2003 15:12:06 +0200 From: Jens Axboe To: Marcelo Tosatti Cc: Andrea Arcangeli , Chris Mason , lkml , "Stephen C. Tweedie" , Alan Cox , Jeff Garzik , Andrew Morton , Alexander Viro Subject: Re: RFC on io-stalls patch Message-ID: <20030714131206.GJ833@suse.de> References: <20030710135747.GT825@suse.de> <1057932804.13313.58.camel@tiny.suse.com> <20030712073710.GK843@suse.de> <1058034751.13318.95.camel@tiny.suse.com> <20030713090116.GU843@suse.de> <20030713191921.GI16313@dualathlon.random> <20030714054918.GD843@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jul 14 2003, Marcelo Tosatti wrote: > > > On Mon, 14 Jul 2003, Jens Axboe wrote: > > > On Sun, Jul 13 2003, Andrea Arcangeli wrote: > > > On Sun, Jul 13, 2003 at 11:01:16AM +0200, Jens Axboe wrote: > > > > No I don't have anything specific, it just seems like a bad heuristic to > > > > get rid of. I can try and do some testing tomorrow. I do feel strongly > > > > > > well, it's not an heuristic, it's a simplification and it will certainly > > > won't provide any benefit (besides saving some hundred kbytes of ram per > > > harddisk that is a minor benefit). > > > > You are missing my point - I don't care about loosing the extra request > > list, I never said anything about that in this thread. I care about > > loosing the reserved requests for reads. And we can do that just fine > > with just holding back a handful of requests. > > > > > > that we should at least make sure to reserve a few requests for reads > > > > exclusively, even if you don't agree with the oversized check. Anything > > > > else really contradicts all the io testing we have done the past years > > > > that shows how important it is to get a read in ASAP. And doing that in > > > > > > Important for latency or throughput? Do you know which is the benchmarks > > > that returned better results with the two queues, what's the theory > > > behind this? > > > > Forget the two queues, noone has said anything about that. The reserved > > reads are important for latency reasons, not throughput. > > So Jens, > > Please bench (as you said you would), and send us the results. > > Its very important. Yes of course I'll send the results, at the current rate (they are running on the box) it probably wont be before tomorrow though. -- Jens Axboe