Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754526Ab0G1X5X (ORCPT ); Wed, 28 Jul 2010 19:57:23 -0400 Received: from bombadil.infradead.org ([18.85.46.34]:58953 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750730Ab0G1X5U (ORCPT ); Wed, 28 Jul 2010 19:57:20 -0400 Date: Wed, 28 Jul 2010 19:57:16 -0400 From: Christoph Hellwig To: Vivek Goyal Cc: Heinz Diehl , linux-kernel@vger.kernel.org, jaxboe@fusionio.com, nauman@google.com, dpshah@google.com, guijianfeng@cn.fujitsu.com, jmoyer@redhat.com, czoccolo@gmail.com Subject: Re: [RFC PATCH] cfq-iosched: IOPS mode for group scheduling and new group_idle tunable Message-ID: <20100728235716.GA12945@infradead.org> 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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100728202212.GD16314@redhat.com> User-Agent: Mutt/1.5.20 (2009-08-17) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1126 Lines: 24 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? 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. -- 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/