From: Jeff Moyer Subject: Re: [patch/rft] jbd2: tag journal writes as metadata I/O Date: Mon, 05 Apr 2010 16:41:48 -0400 Message-ID: References: <20100405175205.GA4681@thunk.org> <20100405194803.GC23670@thunk.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, jens.axboe@oracle.com, esandeen@redhat.com To: tytso@mit.edu Return-path: Received: from mx1.redhat.com ([209.132.183.28]:55076 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756219Ab0DEUlz (ORCPT ); Mon, 5 Apr 2010 16:41:55 -0400 In-Reply-To: (Jeff Moyer's message of "Mon, 05 Apr 2010 16:34:36 -0400") Sender: linux-ext4-owner@vger.kernel.org List-ID: Jeff Moyer writes: > tytso@mit.edu writes: > >> On Mon, Apr 05, 2010 at 02:36:07PM -0400, Jeff Moyer wrote: >>> > >>> > What benchmark were you using to test small file writes? This looks >>> > good to me as well, but we might want to do some extra benchmarking >>> > just to be sure we're not accidentally introducing a performance >>> > regression. >>> >>> iozone showed regressions for write and re-write in runs that include >>> fsync timings for small files (<8MB). Here's the command line used for >>> testing: >>> >>> iozone -az -n 4k -g 2048m -y 1k -q 1m -e >> >> iozone is showing performance regressions or performance improvements? >> I thought the point of this patch was to improve iozone benchmarks? > > Sorry, Ted, what I meant to say was that iozone showed differences > between deadline and cfq, where cfq's performance was much worse than > deadline's. And to be 100% clear, with the patch, the performance differences between deadline and cfq were in the noise. Cheers, Jeff