Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757568Ab0G2TkB (ORCPT ); Thu, 29 Jul 2010 15:40:01 -0400 Received: from mx1.redhat.com ([209.132.183.28]:51213 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754856Ab0G2Tj5 (ORCPT ); Thu, 29 Jul 2010 15:39:57 -0400 From: Jeff Moyer To: Vivek Goyal Cc: Christoph Hellwig , Heinz Diehl , linux-kernel@vger.kernel.org, jaxboe@fusionio.com, nauman@google.com, dpshah@google.com, guijianfeng@cn.fujitsu.com, czoccolo@gmail.com, "Ted Ts'o" Subject: Re: cfq fsync patch testing results (Was: Re: [RFC PATCH] cfq-iosched: IOPS mode for group scheduling and new group_idle tunable) References: <1279834172-4227-1-git-send-email-vgoyal@redhat.com> <20100723140343.GA8478@fancy-poultry.org> <20100723141303.GB13104@redhat.com> <20100723145631.GA8844@fancy-poultry.org> <20100723183720.GD13104@redhat.com> <20100724080613.GA6554@fancy-poultry.org> <20100728202212.GD16314@redhat.com> <20100728235716.GA12945@infradead.org> <20100729043443.GB21736@redhat.com> <20100729145632.GC25863@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: Thu, 29 Jul 2010 15:39:37 -0400 In-Reply-To: <20100729145632.GC25863@redhat.com> (Vivek Goyal's message of "Thu, 29 Jul 2010 10:56:32 -0400") Message-ID: User-Agent: Gnus/5.110011 (No Gnus v0.11) Emacs/23.1 (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: 2473 Lines: 65 Vivek Goyal writes: > On Thu, Jul 29, 2010 at 12:34:43AM -0400, Vivek Goyal wrote: >> On Wed, Jul 28, 2010 at 07:57:16PM -0400, Christoph Hellwig wrote: >> > On Wed, Jul 28, 2010 at 04:22:12PM -0400, Vivek Goyal wrote: >> > > I also did "time firefox &" testing to see how long firefox takes to >> > > launch when linus torture test is running and without patch it took >> > > around 20 seconds and with patch it took around 17 seconds. >> > > >> > > So to me above test results suggest that this patch does not worsen >> > > the performance. In fact it helps. (at least on ext3 file system.) >> > > >> > > Not sure why are you seeing different results with XFS. >> > >> > So why didn't you test it with XFS to verify his results? >> >> Just got little lazy. Find the testing results with ext3, ext4 and >> xfs below. >> >> > We all know >> > that different filesystems have different I/O patters, and we have >> > a history of really nasty regressions in one filesystem by good meaning >> > changes to the I/O scheduler. >> > >> > ext3 in fact is a particularly bad test case as it not only doesn't have >> > I/O barriers enabled, but also has particularly bad I/O patterns >> > compared to modern filesystems. A string of numbers is hard for me to parse. In the hopes that this will help others, here is some awk-fu that I shamelessly stole from the internets: awk '{total1+=$3; total2+=$6; array1[NR]=$3; array2[NR]=$6} END{for(x=1;x<=NR;x++){sumsq1+=((array1[x]-(total1/NR))**2); sumsq2+=((array2[x]-(total2/NR))**2);}print total1/NR " " sqrt(sumsq1/NR) " " total2/NR " " sqrt(sumsq2/NR)}' >> Ext3 results >> ============ >> ext3 (2.6.35-rc6) ext3 (35-rc6-fsync) >> ----------------- ------------------- avg stddev avg stddev 3.8953 2.80654 0.587943 1.22399 >> >> XFS results >> ========== >> XFS (2.6.35-rc6) XFS (with fsync patch) 2.2538 0.95565 2.11869 0.649704 >> Ext4 >> ==== >> ext4 (vanilla) ext4 (patched) 8.57177 9.54596 9.41524 10.4037 > ext3 (barrier=1) ext3 (barrier=1) 2.40316 1.26992 1.82272 0.922305 It is interesting that ext4 does worse with the patch (though, realistically, not by much). 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/