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Date: Thu, 22 Nov 2012 02:21:22 +0100
From: Ingo Molnar <mingo@kernel.org>
To: Alex Shi <lkml.alex@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
        David Rientjes <rientjes@google.com>, Mel Gorman <mgorman@suse.de>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
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        Andrea Arcangeli <aarcange@redhat.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Johannes Weiner <hannes@cmpxchg.org>, Hugh Dickins <hughd@google.com>
Subject: Re: numa/core regressions fixed - more testers wanted
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* Alex Shi <lkml.alex@gmail.com> wrote:

> >
> > Those of you who would like to test all the latest patches are
> > welcome to pick up latest bits at tip:master:
> >
> >    git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git master
> >
> 
> I am wondering if it is a problem, but it still exists on HEAD: c418de93e39891
> http://article.gmane.org/gmane.linux.kernel.mm/90131/match=compiled+with+name+pl+and+start+it+on+my
> 
> like when just start 4 pl tasks, often 3 were running on node 
> 0, and 1 was running on node 1. The old balance will average 
> assign tasks to different node, different core.

This is "normal" in the sense that the current mainline 
scheduler is (supposed to be) doing something similar: if the 
node is still within capacity, then there's no reason to move 
those threads.

OTOH, I think with NUMA balancing we indeed want to spread them 
better, if those tasks do not share memory with each other but 
use their own memory. If they share memory then they should 
remain on the same node if possible.

Thanks,

	Ingo