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Subject: Re: [OMPI users] core binding confusion
From: Ralph Castain (rhc_at_[hidden])
Date: 2012-03-06 10:40:02


On Tue, Mar 6, 2012 at 7:28 AM, Dave Love <d.love_at_[hidden]> wrote:

> Could someone confirm whether this is a bug or misunderstanding the doc
> (in which case it's not just me, and it needs clarifying!)? I haven't
> looked at the current code in the hope of a quick authoritative answer.
>
> This is with 1.5.5rc3, originally on Interlagos, but also checked on
> Magny Cours. It's also seen on two Interlagos with different physical
> numbering of the logical processors.
>
> On a 48-core Magny Cours with
>
> mpirun --bysocket --bind-to-core --report-bindings -np 48
>
> what I get is two processes per core, e.g.:
>
> [node247:09521] [[58099,0],0] odls:default:fork binding child
> [[58099,1],14] to socket 2 cpus 4000
> ...
> [node247:09521] [[58099,0],0] odls:default:fork binding child
> [[58099,1],38] to socket 2 cpus 4000
>
> and hwloc-ps confirms the situation. However, I (and my boss, who did
> it originally) expect one per core. With --bycore we do see one per
> core, of course.
>
> Is that actually expected?
>

Well, no - it shouldn't do that, so I would expect it is a bug. Will try to
look at it, but probably won't happen until next week due to travel.

>
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