Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754082AbZIIUMO (ORCPT ); Wed, 9 Sep 2009 16:12:14 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753850AbZIIUMO (ORCPT ); Wed, 9 Sep 2009 16:12:14 -0400 Received: from mail-in-05.arcor-online.net ([151.189.21.45]:57981 "EHLO mail-in-05.arcor-online.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752612AbZIIUMN (ORCPT ); Wed, 9 Sep 2009 16:12:13 -0400 X-DKIM: Sendmail DKIM Filter v2.8.2 mail-in-06.arcor-online.net 4702B39A826 Message-ID: <4AA80C1E.2080901@arcor.de> Date: Wed, 09 Sep 2009 23:12:14 +0300 From: Nikos Chantziaras Organization: Lucas Barks User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.1) Gecko/20090826 Thunderbird/3.0b3 MIME-Version: 1.0 To: Ingo Molnar CC: Jens Axboe , Mike Galbraith , Peter Zijlstra , Con Kolivas , linux-kernel@vger.kernel.org Subject: Re: BFS vs. mainline scheduler benchmarks and measurements References: <20090907173846.GB18599@kernel.dk> <20090907204458.GJ18599@kernel.dk> <20090908091304.GQ18599@kernel.dk> <1252423398.7746.97.camel@twins> <20090908203409.GJ18599@kernel.dk> <20090909061308.GA28109@elte.hu> <1252486344.28645.18.camel@marge.simson.net> <20090909091009.GR18599@kernel.dk> <20090909115429.GY18599@kernel.dk> <20090909122006.GA18599@kernel.dk> <20090909180404.GA11027@elte.hu> In-Reply-To: <20090909180404.GA11027@elte.hu> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2641 Lines: 91 On 09/09/2009 09:04 PM, Ingo Molnar wrote: > [...] > * Jens Axboe wrote: > >> On Wed, Sep 09 2009, Jens Axboe wrote: >> [...] >> BFS210 runs on the laptop (dual core intel core duo). With make -j4 >> running, I clock the following latt -c8 'sleep 10' latencies: >> >> -rc9 >> >> Max 17895 usec >> Avg 8028 usec >> Stdev 5948 usec >> Stdev mean 405 usec >> >> Max 17896 usec >> Avg 4951 usec >> Stdev 6278 usec >> Stdev mean 427 usec >> >> Max 17885 usec >> Avg 5526 usec >> Stdev 6819 usec >> Stdev mean 464 usec >> >> -rc9 + mike >> >> Max 6061 usec >> Avg 3797 usec >> Stdev 1726 usec >> Stdev mean 117 usec >> >> Max 5122 usec >> Avg 3958 usec >> Stdev 1697 usec >> Stdev mean 115 usec >> >> Max 6691 usec >> Avg 2130 usec >> Stdev 2165 usec >> Stdev mean 147 usec > > At least in my tests these latencies were mainly due to a bug in > latt.c - i've attached the fixed version. > > The other reason was wakeup batching. If you do this: > > echo 0> /proc/sys/kernel/sched_wakeup_granularity_ns > > ... then you can switch on insta-wakeups on -tip too. > > With a dual-core box and a make -j4 background job running, on > latest -tip i get the following latencies: > > $ ./latt -c8 sleep 30 > Entries: 656 (clients=8) > > Averages: > ------------------------------ > Max 158 usec > Avg 12 usec > Stdev 10 usec With your version of latt.c, I get these results with 2.6-tip vs 2.6.31-rc9-bfs: (mainline) Averages: ------------------------------ Max 50 usec Avg 12 usec Stdev 3 usec (BFS) Averages: ------------------------------ Max 474 usec Avg 11 usec Stdev 16 usec However, the interactivity problems still remain. Does that mean it's not a latency issue? -- 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/