Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933843AbXEPUkL (ORCPT ); Wed, 16 May 2007 16:40:11 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1762866AbXEPUj5 (ORCPT ); Wed, 16 May 2007 16:39:57 -0400 Received: from smtp2.linux-foundation.org ([207.189.120.14]:50003 "EHLO smtp2.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1762552AbXEPUj4 (ORCPT ); Wed, 16 May 2007 16:39:56 -0400 Date: Wed, 16 May 2007 13:37:26 -0700 From: Andrew Morton To: Chris Mason Cc: Chuck Ebbert , linux-kernel@vger.kernel.org Subject: Re: filesystem benchmarking fun Message-Id: <20070516133726.0c68a65f.akpm@linux-foundation.org> In-Reply-To: <20070516201414.GF26766@think.oraclecorp.com> References: <20070516144205.GV26766@think.oraclecorp.com> <464B2AC2.10206@redhat.com> <20070516171156.GY26766@think.oraclecorp.com> <20070516112515.b6f247b2.akpm@linux-foundation.org> <20070516191339.GA26766@think.oraclecorp.com> <20070516123342.714a11d8.akpm@linux-foundation.org> <20070516195359.GE26766@think.oraclecorp.com> <20070516130413.1fd391bf.akpm@linux-foundation.org> <20070516201414.GF26766@think.oraclecorp.com> X-Mailer: Sylpheed version 2.2.7 (GTK+ 2.8.6; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1277 Lines: 28 On Wed, 16 May 2007 16:14:14 -0400 Chris Mason wrote: > On Wed, May 16, 2007 at 01:04:13PM -0700, Andrew Morton wrote: > > > The good news is that if you let it run long enough, the times > > > stabilize. The bad news is: > > > > > > create dir kernel-86 222MB in 15.85 seconds (14.03 MB/s) > > > create dir kernel-87 222MB in 28.67 seconds (7.76 MB/s) > > > create dir kernel-88 222MB in 18.12 seconds (12.27 MB/s) > > > create dir kernel-89 222MB in 19.77 seconds (11.25 MB/s) > > > > well hang on. Doesn't this just mean that the first few runs were writing > > into pagecache and the later ones were blocking due to dirty-memory limits? > > > > Or do you have a sync in there? > > > There's no sync, but if you watch vmstat you can clearly see the log > flushes, even when the overall create times are 11MB/s. vmstat goes > 30MB/s -> 4MB/s or less, then back up to 30MB/s. How do you know that it is a log flush rather than, say, pdflush hitting the blockdev inode and doing a big seeky write? - 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/