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Subject: Re: [hwloc-devel] Memory affinity
From: Jeff Squyres (jsquyres_at_[hidden])
Date: 2011-02-28 16:44:43


On Feb 28, 2011, at 4:39 PM, Brice Goglin wrote:

>> So: binding + pinning = binding (as long as you can ensure that the binding + pinning was atomic!).
>
> If the application swaps for real, do you really care about NUMA
> locality ? It seems to me that the overhead of accessing distant NUMA
> memory may be negligible against the cost of swapping.

True, but what if the swapping was temporary? The overhead due to swap out/swap in may be tiny in comparison to the longer-lasting effects that it causes (putting your memory far away, when then sucks up memory and bus bandwidth, etc.).

I'm thinking outside the realm of HPC environments, where swapping isn't uncommon.

-- 
Jeff Squyres
jsquyres_at_[hidden]
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