Messages in this thread | | | Date | Thu, 24 Feb 2011 08:25:43 +1030 | From | Arthur Marsh <> | Subject | Re: [Alsa-user] new source of MIDI playback slow-down identified - 5a03b051ed87e72b959f32a86054e1142ac4cf55 thp: use compaction in kswapd for GFP_ATOMIC order > 0 |
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Andrea Arcangeli wrote, on 24/02/11 07:55: > 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.
One more combination I tried:
Mel Gorman's mm/compaction.c patch with Andrea Archangeli's kswapd-high_wmark + compaction-no-kswapd-3 patches - kswapd0 CPU less than 2 percent and no noticable slowdown of MIDI playback.
This may be better performing than compaction-no-kswapd-3 alone but is not conclusive.
> > 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?)
If you can send me an updated patch compaction-no-kswapd-3 (I presume that kswapd-high_wmark is still needed) it would be easier for me to apply.
> > 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 >
Arthur.
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