From: Martin Knoblauch Subject: Re: regression: 100% io-wait with 2.6.24-rcX Date: Thu, 17 Jan 2008 05:52:58 -0800 (PST) Message-ID: <400343.10983.qm@web32611.mail.mud.yahoo.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Mike Snitzer , Peter Zijlstra , jplatte@naasa.net, Ingo Molnar , linux-kernel@vger.kernel.org, "linux-ext4@vger.kernel.org" , Linus Torvalds To: Fengguang Wu Return-path: Received: from web32611.mail.mud.yahoo.com ([68.142.207.238]:47438 "HELO web32611.mail.mud.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751336AbYAQNw7 (ORCPT ); Thu, 17 Jan 2008 08:52:59 -0500 Sender: linux-ext4-owner@vger.kernel.org List-ID: ----- Original Message ---- > From: Fengguang Wu > To: Martin Knoblauch > Cc: Mike Snitzer ; Peter Zijlstra ; jplatte@naasa.net; Ingo Molnar ; linux-kernel@vger.kernel.org; "linux-ext4@vger.kernel.org" ; Linus Torvalds > Sent: Wednesday, January 16, 2008 1:00:04 PM > Subject: Re: regression: 100% io-wait with 2.6.24-rcX > > On Wed, Jan 16, 2008 at 01:26:41AM -0800, Martin Knoblauch wrote: > > > For those interested in using your writeback improvements in > > > production sooner rather than later (primarily with ext3); what > > > recommendations do you have? Just heavily test our own 2.6.24 > + > your > > > evolving "close, but not ready for merge" -mm writeback patchset? > > > > > Hi Fengguang, Mike, > > > > I can add myself to Mikes question. It would be good to know > a > "roadmap" for the writeback changes. Testing 2.6.24-rcX so far has > been > showing quite nice improvement of the overall writeback situation and > it > would be sad to see this [partially] gone in 2.6.24-final. > Linus > apparently already has reverted "...2250b". I will definitely repeat my > tests > with -rc8. and report. > > Thank you, Martin. Can you help test this patch on 2.6.24-rc7? > Maybe we can push it to 2.6.24 after your testing. > Hi Fengguang, something really bad has happened between -rc3 and -rc6. Embarrassingly I did not catch that earlier :-( Compared to the numbers I posted in http://lkml.org/lkml/2007/10/26/208 , dd1 is now at 60 MB/sec (slight plus), while dd2/dd3 suck the same way as in pre 2.6.24. The only test that is still good is mix3, which I attribute to the per-BDI stuff. At the moment I am frantically trying to find when things went down. I did run -rc8 and rc8+yourpatch. No difference to what I see with -rc6. Sorry that I cannot provide any input to your patch. Depressed Martin