Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756986AbZJCTIl (ORCPT ); Sat, 3 Oct 2009 15:08:41 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754756AbZJCTIl (ORCPT ); Sat, 3 Oct 2009 15:08:41 -0400 Received: from mail.gmx.net ([213.165.64.20]:42595 "HELO mail.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1754357AbZJCTIk (ORCPT ); Sat, 3 Oct 2009 15:08:40 -0400 X-Authenticated: #14349625 X-Provags-ID: V01U2FsdGVkX19SrQZkh+JSwRfExomLiMFp9a4JPdwFdkHNmiUDp5 +2tpdD+DVfHgWW Subject: Re: Do not overload dispatch queue (Was: Re: IO scheduler based IO controller V10) From: Mike Galbraith To: Jens Axboe 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 In-Reply-To: <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> <20091003173532.GG31616@kernel.dk> Content-Type: text/plain Date: Sat, 03 Oct 2009 21:07:44 +0200 Message-Id: <1254596864.7153.9.camel@marge.simson.net> Mime-Version: 1.0 X-Mailer: Evolution 2.24.1.1 Content-Transfer-Encoding: 7bit X-Y-GMX-Trusted: 0 X-FuHaFi: 0.57 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3491 Lines: 72 On Sat, 2009-10-03 at 19:35 +0200, Jens Axboe wrote: > 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. Yeah, but it's a double edged sword, _maybe_ cut too far in the other direction. (impression) > > 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. No, not bad at all, still a large win over stock. > 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. I'm unsure feel wise. Disk is sounding too seeky, which worries me. -Mike -- 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/