Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752308AbXE3Hl3 (ORCPT ); Wed, 30 May 2007 03:41:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751307AbXE3HlW (ORCPT ); Wed, 30 May 2007 03:41:22 -0400 Received: from brick.kernel.dk ([80.160.20.94]:14568 "EHLO kernel.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751247AbXE3HlV (ORCPT ); Wed, 30 May 2007 03:41:21 -0400 Date: Wed, 30 May 2007 09:40:32 +0200 From: Jens Axboe To: Zach Brown Cc: linux-kernel@vger.kernel.org, Ingo Molnar , Linus Torvalds , Arjan van de Ven , Christoph Hellwig , Andrew Morton , Alan Cox , Ulrich Drepper , Evgeniy Polyakov , "David S. Miller" , Suparna Bhattacharya , Davide Libenzi , Thomas Gleixner Subject: Re: Syslets, Threadlets, generic AIO support, v6 Message-ID: <20070530074031.GV15559@kernel.dk> References: <20070529212718.GH7875@mami.zabbo.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070529212718.GH7875@mami.zabbo.net> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1071 Lines: 28 On Tue, May 29 2007, Zach Brown wrote: Thanks for picking this up, Zach! > - cfq gets confused, share io_context amongst threads? Yeah, it'll confuse CFQ a lot actually. The threads either need to share an io context (clean approach, however will introduce locking for things that were previously lockless), or CFQ needs to get better support for cooperating processes. The problem is that CFQ will wait for a dependent IO for a given process, which may arrive from a totally unrelated process. For the fio testing, we can make some improvements there. Right now you don't get any concurrency of the io requests if you set eg iodepth=32, as the 32 requests will be submitted as a linked chain of atoms. For io saturation, that's not really what you want. I'll take a stab at improving both of the above. -- 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/