Date: Mon, 26 Jun 2017 18:12:50 +0200
From: Peter Zijlstra <peterz@infradead.org>
To: Rik van Riel <riel@redhat.com>
Cc: linux-kernel@vger.kernel.org, jhladky@redhat.com, mingo@kernel.org,
        mgorman@suse.de
Subject: Re: [PATCH 4/4] sched,fair: remove effective_load
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On Mon, Jun 26, 2017 at 11:20:54AM -0400, Rik van Riel wrote:

> Oh, indeed.  I guess in wake_affine() we should test
> whether the CPUs are in the same NUMA node, rather than
> doing cpus_share_cache() ?

Well, since select_idle_sibling() is on LLC; the early test on
cpus_share_cache(prev,this) seems to actually make sense.

But then cutting out all the other bits seems wrong. Not in the least
because !NUMA_BALACING should also still keep working.

> Or, alternatively, have an update_numa_stats() variant
> for numa_wake_affine() that works on the LLC level?

I think we want to retain the existing behaviour for everything
larger than LLC, and when NUMA_BALANCING, smaller than NUMA.

Also note that your use of task_h_load() in the new numa thing suffers
from exactly the problem effective_load() is trying to solve.