Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756407AbZLKRPS (ORCPT ); Fri, 11 Dec 2009 12:15:18 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754119AbZLKRPP (ORCPT ); Fri, 11 Dec 2009 12:15:15 -0500 Received: from mail-yx0-f187.google.com ([209.85.210.187]:57988 "EHLO mail-yx0-f187.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754050AbZLKRPO convert rfc822-to-8bit (ORCPT ); Fri, 11 Dec 2009 12:15:14 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=snNzb/HsARfgULOHi/HmUopyFZ4AeFoEmpifz3L2LfYTWRbTvhPkoEGeg4ShYM9Cku +UGYXBeJzIdT+vaC7p0JAAtn5zfpHGikU2kkDYYfc+349xfE49wk7EFcmDUx+rVu0qvd ubqJLbd85/UlyR/Qx+wdAOUDkhBNeq+owv/d0= MIME-Version: 1.0 In-Reply-To: References: <4b1a3d84.0d0db80a.39d0.ffff814a@mx.google.com> <4e5e476b0912050313k280caa8bjf7c2cf1c5d19c88c@mail.gmail.com> <4e5e476b0912060245x4d64300hb9689243bd712f2c@mail.gmail.com> <4e5e476b0912081243ra071947if9a3edae77fb3861@mail.gmail.com> Date: Fri, 11 Dec 2009 18:15:20 +0100 Message-ID: <4e5e476b0912110915u209b8923m359d9147cc229fea@mail.gmail.com> Subject: Re: [PATCH] cfq-iosched: reduce write depth only if sync was delayed From: Corrado Zoccolo To: Jeff Moyer Cc: Linux-Kernel , Jens Axboe , Vivek Goyal Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1323 Lines: 34 Hi Jeff, On Wed, Dec 9, 2009 at 7:09 PM, Jeff Moyer wrote: > Corrado Zoccolo writes: > >> The numbers look good. Now, there is no penalty in having low_latency >> set for sequential writes, and just a small penalty for random ones. >> The fact that random reads are faster with low_latency set is interesting. >> Is the test is running with your patched tiobench (so that the number >> of random operations is comparable with sequential ones)? > > No, I forgot all about that.  The number of random operations defaults > to 4000, which is pretty low.  I'll re-run the tests with a number > comparable to the sequential runs.  Sorry about that. > N.P. if you have time, can you also re-run the test changing: iosched/fifo_expire_async to 8 ? I hope that reducing the expire_async, will make cfq quicker at switching between the different threads, allowing more parallelism for seq writers on your hw. If this is the case, I think I can try to estimate the fifo_expire_async in the autotuning patch. > Cheers, > Jeff > Thanks Corrado -- 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/