From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262047AbULHHUA (ORCPT ); Wed, 8 Dec 2004 02:20:00 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262048AbULHHT7 (ORCPT ); Wed, 8 Dec 2004 02:19:59 -0500 Received: from smtp111.mail.sc5.yahoo.com ([66.163.170.9]:55673 "HELO smtp111.mail.sc5.yahoo.com") by vger.kernel.org with SMTP id S262047AbULHHT5 (ORCPT ); Wed, 8 Dec 2004 02:19:57 -0500 Subject: Re: Time sliced CFQ io scheduler From: Nick Piggin To: Jens Axboe Cc: Andrew Morton , Andrea Arcangeli , linux-kernel@vger.kernel.org In-Reply-To: <20041208071141.GB19522@suse.de> References: <20041202130457.GC10458@suse.de> <20041202134801.GE10458@suse.de> <20041202114836.6b2e8d3f.akpm@osdl.org> <20041202195232.GA26695@suse.de> <20041208003736.GD16322@dualathlon.random> <1102467253.8095.10.camel@npiggin-nld.site> <20041208013732.GF16322@dualathlon.random> <20041207180033.6699425b.akpm@osdl.org> <20041208065534.GF3035@suse.de> <1102489719.8095.56.camel@npiggin-nld.site> <20041208071141.GB19522@suse.de> Content-Type: text/plain Date: Wed, 08 Dec 2004 18:19:49 +1100 Message-Id: <1102490389.8095.69.camel@npiggin-nld.site> Mime-Version: 1.0 X-Mailer: Evolution 2.0.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2004-12-08 at 08:11 +0100, Jens Axboe wrote: > On Wed, Dec 08 2004, Nick Piggin wrote: > > On Wed, 2004-12-08 at 07:55 +0100, Jens Axboe wrote: > > > Currently I think the time sliced cfq is the best all around. There's > > > still a few kinks to be shaken out, but generally I think the concept is > > > sounder than AS. > > > > > > > But aren't you basically unconditionally allowing a 4ms idle time after > > reads? The complexity of AS (other than all the work we had to do to get > > the block layer to cope with it), is getting it to turn off at (mostly) > > the right times. Other than that, it is basically the deadline > > scheduler. > > Yes, the concept is similar and there will be time wasting currently. > I've got some cases covered that AS doesn't, and there are definitely > some the other way around as well. > Oh? What have you got covered that AS doesn't? (I'm only reading the patch itself, which isn't trivial to follow). > If you have any test cases/programs, I'd like to see them. > Hmm, damn. Lots of stuff. I guess some of the notable ones that I've had trouble with are OraSim (Oracle might give you a copy), Andrew's patch scripts when applying a stack of patches, pgbench... can't really remember any others off the top of my head. I've got a small set of basic test programs that are similar to the sort of tests you've been running in this thread as well.