From mboxrd@z Thu Jan 1 00:00:00 1970 From: Frederic Weisbecker Subject: Re: [PATCH 0/11] Per-bdi writeback flusher threads v9 Date: Thu, 4 Jun 2009 23:37:06 +0200 Message-ID: <20090604213704.GC4862@nowhere> References: <1243511204-2328-1-git-send-email-jens.axboe@oracle.com> <20090604152040.GA6007@nowhere> <20090604120726.708a2211.akpm@linux-foundation.org> <20090604191309.GA4862@nowhere> <20090604195013.GB11363@kernel.dk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Andrew Morton , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, tytso@mit.edu, chris.mason@oracle.com, david@fromorbit.com, hch@infradead.org, jack@suse.cz, yanmin_zhang@linux.intel.com, richard@rsk.demon.co.uk, damien.wyart@free.fr To: Jens Axboe Return-path: Received: from fg-out-1718.google.com ([72.14.220.154]:64725 "EHLO fg-out-1718.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751718AbZFDVnO (ORCPT ); Thu, 4 Jun 2009 17:43:14 -0400 Content-Disposition: inline In-Reply-To: <20090604195013.GB11363@kernel.dk> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Thu, Jun 04, 2009 at 09:50:13PM +0200, Jens Axboe wrote: > On Thu, Jun 04 2009, Frederic Weisbecker wrote: > > On Thu, Jun 04, 2009 at 12:07:26PM -0700, Andrew Morton wrote: > > > On Thu, 4 Jun 2009 17:20:44 +0200 Frederic Weisbecker wrote: > > > > > > > I've just tested it on UP in a single disk. > > > > > > I must say, I'm stunned at the amount of testing which people are > > > performing on this patchset. Normally when someone sends out a > > > patchset it just sort of lands with a dull thud. > > > > > > I'm not sure what Jens did right to make all this happen, but thanks! > > > > > > I don't know how he did either. I was reading theses patches and *something* > > pushed me to my testbox, and then I tested... > > > > Jens, how do you do that? > > Heh, not sure :-) > > But indeed, thanks for the testing. It looks quite interesting. I'm > guessing it probably has to do with who ends up doing the balancing and > that the flusher threads block, it may change the picture a bit. So it > may just be that it'll require a few vm tweaks. I'll definitely look > into it and try and reproduce your results. > > Did you run it a 2nd time on each drive and check if the results were > (approximately) consistent on the two drives? Another snapshot, only with bdi-writeback this time. http://kernel.org/pub/linux/kernel/people/frederic/dbench2.pdf Looks like the same effect but the difference is more quiet this time. I guess there is a good bunch of entropy inside, so it's hard to tell :) I'll test with no op scheduler.