Re: [RFC PATCH 0/4]: affinity-on-next-touch

From: Brice Goglin
Date: Mon Jun 22 2009 - 08:33:55 EST


Lee Schermerhorn wrote:
> On Wed, 2009-06-17 at 09:45 +0200, Stefan Lankes wrote:
>
>>> I've placed the last rebased version in :
>>>
>>> http://free.linux.hp.com/~lts/Patches/PageMigration/2.6.28-rc4-mmotm-
>>> 081110/
>>>
>>>
>> OK! I will try to reconstruct the problem.
>>
>
> Stefan:
>
> Today I rebased the migrate on fault patches to 2.6.30-mmotm-090612...
> [along with my shared policy series atop which they sit in my tree].
> Patches reside in:
>
> http://free.linux.hp.com/~lts/Patches/PageMigration/2.6.30-mmotm-090612-1220/
>
>

I gave this patchset a try and indeed it seems to work fine, thanks a
lot. But the migration performance isn't very good. I am seeing about
540MB/s when doing mbind+touch_all_pages on large buffers on a
quad-barcelona machines. move_pages gets 640MB/s there. And my own
next-touch implementation were near 800MB/s in the past.

I wonder if there is a more general migration performance degradation in
latest Linus git. move_pages performance was supposed to increase by 15%
(more than 700MB/s) thanks to commit dfa33d45 but I don't seem to see
the improvement with git or mmotm. Also migrate_pages seems to have
decreased but it might be older than 2.6.30. I need to find some time to
git bisect all this, otherwise it's hard to compare the performance of
your migrate-on-fault with other older implementations :)

When do you plan to actually submit all your patches for inclusion?

thanks,
Brice

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