Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757460AbZFVQIW (ORCPT ); Mon, 22 Jun 2009 12:08:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757974AbZFVQIA (ORCPT ); Mon, 22 Jun 2009 12:08:00 -0400 Received: from mx2.redhat.com ([66.187.237.31]:45244 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757979AbZFVQH7 (ORCPT ); Mon, 22 Jun 2009 12:07:59 -0400 From: Jeff Moyer To: Vivek Goyal Cc: Balbir Singh , linux-kernel@vger.kernel.org, containers@lists.linux-foundation.org, dm-devel@redhat.com, jens.axboe@oracle.com, nauman@google.com, dpshah@google.com, lizf@cn.fujitsu.com, mikew@google.com, fchecconi@gmail.com, paolo.valente@unimore.it, ryov@valinux.co.jp, fernando@oss.ntt.co.jp, s-uchida@ap.jp.nec.com, taka@valinux.co.jp, guijianfeng@cn.fujitsu.com, dhaval@linux.vnet.ibm.com, righi.andrea@gmail.com, m-ikeda@ds.jp.nec.com, jbaron@redhat.com, agk@redhat.com, snitzer@redhat.com, akpm@linux-foundation.org, peterz@infradead.org Subject: Re: [RFC] IO scheduler based io controller (V5) References: <1245443858-8487-1-git-send-email-vgoyal@redhat.com> <20090621152116.GC3728@balbir.in.ibm.com> <20090622153030.GA15600@redhat.com> <20090622160207.GC15600@redhat.com> X-PGP-KeyID: 1F78E1B4 X-PGP-CertKey: F6FE 280D 8293 F72C 65FD 5A58 1FF8 A7CA 1F78 E1B4 X-PCLoadLetter: What the f**k does that mean? Date: Mon, 22 Jun 2009 12:06:42 -0400 In-Reply-To: <20090622160207.GC15600@redhat.com> (Vivek Goyal's message of "Mon, 22 Jun 2009 12:02:07 -0400") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.0.60 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2133 Lines: 65 Vivek Goyal writes: > On Mon, Jun 22, 2009 at 11:40:42AM -0400, Jeff Moyer wrote: >> Vivek Goyal writes: >> >> > On Sun, Jun 21, 2009 at 08:51:16PM +0530, Balbir Singh wrote: >> >> * Vivek Goyal [2009-06-19 16:37:18]: >> >> >> >> > >> >> > Hi All, >> >> > >> >> > Here is the V5 of the IO controller patches generated on top of 2.6.30. >> >> [snip] >> >> >> >> > Testing >> >> > ======= >> >> > >> >> >> >> [snip] >> >> >> >> I've not been reading through the discussions in complete detail, but >> >> I see no reference to async reads or aio. In the case of aio, aio >> >> presumes the context of the user space process. Could you elaborate on >> >> any testing you've done with these cases? >> >> >> > >> > Hi Balbir, >> > >> > So far I had not done any testing with AIO. I have done some just now. >> > Here are the results. >> > >> > Test1 (AIO reads) >> > ================ >> > Set up two fio, AIO read jobs in two cgroup with weight 1000 and 500 >> > respectively. I am using cfq scheduler. Following are some lines from my test >> > script. >> > >> > =================================================================== >> > fio_args="--ioengine=libaio --rw=read --size=512M" >> >> AIO doesn't make sense without O_DIRECT. >> > > Ok, here are the read results with --direct=1 for reads. In previous posting, > writes were already direct. > > test1 statistics: time=8 16 20796 sectors=8 16 1049648 > test2 statistics: time=8 16 10551 sectors=8 16 581160 > > > Not sure why reads are so slow with --direct=1? In the previous test > (no direct IO), I had cleared the caches using > (echo 3 > /proc/sys/vm/drop_caches) so reads could not have come from page > cache? O_DIRECT bypasses the page cache, and hence the readahead code. Try driving deeper queue depths and/or using larger I/O sizes. Cheers, Jeff -- 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/