Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755998Ab1BWV0Y (ORCPT ); Wed, 23 Feb 2011 16:26:24 -0500 Received: from mx1.redhat.com ([209.132.183.28]:31631 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753150Ab1BWV0W (ORCPT ); Wed, 23 Feb 2011 16:26:22 -0500 Date: Wed, 23 Feb 2011 22:25:41 +0100 From: Andrea Arcangeli To: Arthur Marsh Cc: Clemens Ladisch , alsa-user@lists.sourceforge.net, linux-kernel@vger.kernel.org, Mel Gorman Subject: Re: [Alsa-user] new source of MIDI playback slow-down identified - 5a03b051ed87e72b959f32a86054e1142ac4cf55 thp: use compaction in kswapd for GFP_ATOMIC order > 0 Message-ID: <20110223212541.GV31195@random.random> References: <4D6367B3.9050306@googlemail.com> <20110222134047.GT13092@random.random> <20110222161513.GC13092@random.random> <4D63F6C0.7060204@internode.on.net> <20110223162432.GL31195@random.random> <20110223165550.GP31195@random.random> <4D65691E.9080600@internode.on.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4D65691E.9080600@internode.on.net> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2483 Lines: 54 On Thu, Feb 24, 2011 at 06:37:58AM +1030, Arthur Marsh wrote: > kswapd-high_wmark + compaction-kswapd-2 - kswapd0 CPU up to 11 percent > and slightly less pronounced slowdowns of MIDI playback compared to > previous patches. > > kswapd-high_wmark + compaction-no-kswapd-3 - kswapd0 CPU up to 2.3 > percent and no noticable slowdown of MIDI playback. > > Mel Gorman's mm/compaction.c patch - kswapd0 CPU up to 20 percent and no > noticable slowdown of MIDI playback. > > Thanks everyone for the help with this. Ok then I think it's safer to go with compaction-no-kswapd-3. I also created a git tree in case anybody else wants to test in easier way. git clone --reference linux-2.6.git git://git.kernel.org/pub/scm/linux/kernel/git/andrea/aa.git (or "git clone git://git.kernel.org/pub/scm/linux/kernel/git/andrea/aa.git") cd aa git checkout -f 3d74399aaece29047beba13a81650538af8db67a (compaction-kswapd+compaction_alloc_lowlat) git checkout -f f048d0082bd3c6a1cc3f5e67aa5ef83d1561ec27 (compaction-no-kswapd+rest+compaction_alloc_lowlat) git checkout -f 859e705548f7377b1803b05b2904bae77495fd1e (only compaction_alloc_lowlat) http://git.kernel.org/?p=linux/kernel/git/andrea/aa.git;a=shortlog;h=3d74399aaece29047beba13a81650538af8db67a http://git.kernel.org/?p=linux/kernel/git/andrea/aa.git;a=shortlog;h=f048d0082bd3c6a1cc3f5e67aa5ef83d1561ec27 http://git.kernel.org/?p=linux/kernel/git/andrea/aa.git;a=shortlog;h=859e705548f7377b1803b05b2904bae77495fd1e Arthur could you give one more spin to the 3d74399aaece29047beba13a81650538af8db67a tree? (or do you prefer an updated patch compaction-kswapd-3?) I'd like to get 3d74399aaece29047beba13a81650538af8db67a tested again because I did one more modification included in the git version compared to the patch version (nr_slab was not always initialized and it could lead to slightly higher kswapd cpu load than intended). I doubt it will help though (just in case). Mel what you think? If f048d0082bd3c6a1cc3f5e67aa5ef83d1561ec27 is still the only one that shows no regression, I think it's safe to apply it to 2.6.38 and revert the compaction in kswapd feature. Then we can add compaction to kswapd later with no hurry. Thanks a lot for the help and quick feedback! Andrea -- 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/