From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sonny Rao Subject: Re: ext3 writepages ? Date: Wed, 9 Feb 2005 16:11:23 -0500 Message-ID: <20050209211123.GA10554@kevlar.burdell.org> References: <1107358324.3503.424.camel@dyn318077bld.beaverton.ibm.com> <20050202201953.GA2728@kevlar.burdell.org> <1107445897.3503.465.camel@dyn318077bld.beaverton.ibm.com> <20050203205011.GA30671@kevlar.burdell.org> <20050208013351.GE2635@schnapps.adilger.int> <20050208053808.GA31566@kevlar.burdell.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-fsdevel@vger.kernel.org, Badari Pulavarty Received: from dsl027-162-124.atl1.dsl.speakeasy.net ([216.27.162.124]:45977 "EHLO kevlar.burdell.org") by vger.kernel.org with ESMTP id S261931AbVBIVYd (ORCPT ); Wed, 9 Feb 2005 16:24:33 -0500 To: Andreas Dilger Content-Disposition: inline In-Reply-To: <20050208053808.GA31566@kevlar.burdell.org> Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On Tue, Feb 08, 2005 at 12:38:08AM -0500, Sonny Rao wrote: > On Mon, Feb 07, 2005 at 06:33:51PM -0700, Andreas Dilger wrote: > > On Feb 03, 2005 15:50 -0500, Sonny Rao wrote: > > > Well, from what I can tell, my patch doesn't seem to make much of a > > > difference in write throughput other than allowing multi-page bios to > > > be sent down and cutting down on buffer_head usage. > > > > Even if it doesn't make a difference in performance, it might reduce the > > CPU usage. Did you check that at all? > > No I didn't, I'll check that out and post back. > > Sonny Ok, I take it back, on a raid device I saw a significant increase in throughput and approximately equal cpu utilization. I was comparing the wrong data points before.. oops. Sequential overwrite went from 75.6 MB/sec to 87.7 MB/sec both with an average CPU utilization of 73% for both. So, I see a 16% improvement in throughput for this test case and a corresponding increase in efficiency. Although, after reading what SCT wrote about writepage and writepages needing to have a transaction handle, in some cases, that might make the proper writepages code significantly more complex than my two-bit hack. Still, I think it's worth it. Sonny