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Subject: Re: [hwloc-devel] Some practical hwloc API feedback
From: Jeff Squyres (jsquyres_at_[hidden])
Date: 2011-09-24 07:46:29

On Sep 22, 2011, at 5:05 PM, Brice Goglin wrote:

> No, the level always contain all elements of the same type (+depth for
> caches), even if they are not at the same "distance" to the root (not
> "depth").
> Let's say you have two single-core sockets. One with no cache. One with
> a L1.
> What happens is:
> * first level/depth is socket, contains two sockets, cover all cores.
> * level 2 is L2, single element, *does not cover all cores*
> * level 3 is core, two elements.
> The funky thing here is that the parent/child links between the first
> socket and its core go across level 2 because nothing matches there. In
> the first socket, you have Socket(depth1)->Core(depth3) while in the
> second socket you have Socket(depth1)->Cache(depth2)->Core(depth3)

Huh. I didn't know / had forgotten this.

I think we definitely need to call this out in the docs.

Jeff Squyres
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