Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754445AbZJCRgL (ORCPT ); Sat, 3 Oct 2009 13:36:11 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751331AbZJCRgL (ORCPT ); Sat, 3 Oct 2009 13:36:11 -0400 Received: from brick.kernel.dk ([93.163.65.50]:32905 "EHLO kernel.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751163AbZJCRgK (ORCPT ); Sat, 3 Oct 2009 13:36:10 -0400 Date: Sat, 3 Oct 2009 19:35:32 +0200 From: Jens Axboe To: Mike Galbraith Cc: Vivek Goyal , Ingo Molnar , Linus Torvalds , Ulrich Lukas , linux-kernel@vger.kernel.org, containers@lists.linux-foundation.org, dm-devel@redhat.com, nauman@google.com, dpshah@google.com, lizf@cn.fujitsu.com, mikew@google.com, fchecconi@gmail.com, paolo.valente@unimore.it, ryov@valinux.co.jp, fernando@oss.ntt.co.jp, jmoyer@redhat.com, dhaval@linux.vnet.ibm.com, balbir@linux.vnet.ibm.com, righi.andrea@gmail.com, m-ikeda@ds.jp.nec.com, agk@redhat.com, akpm@linux-foundation.org, peterz@infradead.org, jmarchan@redhat.com, riel@redhat.com Subject: Re: Do not overload dispatch queue (Was: Re: IO scheduler based IO controller V10) Message-ID: <20091003173532.GG31616@kernel.dk> References: <1254549378.8299.21.camel@marge.simson.net> <20091003112915.GA12925@redhat.com> <20091003124049.GB12925@redhat.com> <20091003132115.GB31616@kernel.dk> <20091003135623.GD12925@redhat.com> <1254578553.7499.5.camel@marge.simson.net> <20091003142840.GE31616@kernel.dk> <1254581496.8293.8.camel@marge.simson.net> <20091003151445.GF31616@kernel.dk> <1254585420.7539.2.camel@marge.simson.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1254585420.7539.2.camel@marge.simson.net> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3121 Lines: 65 On Sat, Oct 03 2009, Mike Galbraith wrote: > On Sat, 2009-10-03 at 17:14 +0200, Jens Axboe wrote: > > On Sat, Oct 03 2009, Mike Galbraith wrote: > > > On Sat, 2009-10-03 at 16:28 +0200, Jens Axboe wrote: > > > > On Sat, Oct 03 2009, Mike Galbraith wrote: > > > > > On Sat, 2009-10-03 at 09:56 -0400, Vivek Goyal wrote: > > > > > > > > > > > I have kept the overload delay period as "cfq_slice_sync" same as Mike had > > > > > > done. We shall have to experiment what is a good waiting perioed. Is 100ms > > > > > > too long if we are waiting for a request from same process which recently > > > > > > finished IO and we did not enable idle on it. > > > > > > > > > > > > I guess we can tweak the delay period as we move along. > > > > > > > > > > I kept the delay period very short to minimize possible damage. Without > > > > > the idle thing, it wasn't enough, but with, worked a treat, as does your > > > > > patch. > > > > > > > > Can you test the current line up of patches in for-linus? It has the > > > > ramp up I talked about included as well. > > > > > > Well, it hasn't hit git.kernel.org yet, it's at... > > > > > > * block-for-linus 1d22351 cfq-iosched: add a knob for desktop interactiveness > > > > It's the top three patches here, kernel.org sync sometimes takes a > > while... > > > > http://git.kernel.dk/?p=linux-2.6-block.git;a=shortlog;h=refs/heads/for-linus > > Ok, already had the first two in, added the last. > > Entered uncharted territory for konsole -e exit, but lost a bit of > throughput for home-brew concurrent git test. > > perf stat 1.70 1.94 1.32 1.89 1.87 1.7 fairness=1 overload_delay=1 > 1.55 1.79 1.38 1.53 1.57 1.5 desktop=1 +last_end_sync > 1.09 0.87 1.11 0.96 1.11 1.0 block-for-linus So that's pure goodness, at least. > perf stat testo.sh Avg > 108.12 106.33 106.34 97.00 106.52 104.8 1.000 fairness=0 overload_delay=0 > 93.98 102.44 94.47 97.70 98.90 97.4 .929 fairness=0 overload_delay=1 > 90.87 95.40 95.79 93.09 94.25 93.8 .895 fairness=1 overload_delay=0 > 89.93 90.57 89.13 93.43 93.72 91.3 .871 fairness=1 overload_delay=1 > 89.81 88.82 91.56 96.57 89.38 91.2 .870 desktop=1 +last_end_sync > 92.61 94.60 92.35 93.17 94.05 93.3 .890 block-for-linus Doesn't look too bad, all things considered. Apart from "stock" cfq, it's consistent. And being consistent is a Good Thing. Performance wise, it's losing out to "stock" but looks pretty competetive otherwise. So far that looks like a winner. The dictator wanted good latency, he's getting good latency. I'll continue working on this on monday, while I'm waiting for delivery of the Trabant. -- Jens Axboe -- 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/