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Subject: Re: [OMPI users] How to replace --cpus-per-proc by --map-by
From: tmishima_at_[hidden]
Date: 2014-03-27 05:11:47


Mapping and binding is related to so called process affinity.
It's a bit difficult for me to explain ...

So please see this URL below(especially the first half part
of it - from 1 to 20 pages):
http://www.slideshare.net/jsquyres/open-mpi-explorations-in-process-affinity-eurompi13-presentation

Although these slides by Jeff are the explanation for LAMA,
which is another mapping system installed in the openmpi-1.7
series, I guess you can easily understand what is mapping and
binding in general terms.

Tetsuya

> Thank you Tetsuya - it worked.
>
> Btw. what's the difference between mapping and binding? I think I am bit
confused here.
>
> Thank you,
> Saliya
>
>
> On Thu, Mar 27, 2014 at 4:19 AM, <tmishima_at_[hidden]>wrote:
>
>
> Hi Saliya,
>
> What you want to do is map-by node. So please try below:
>
> -np 2 --map-by node:pe=4 --bind-to core
>
> You might not need to add --bind-to core, because it's default binding.
>
> Tetsuya
>
> > Hi,
> >
> > I see in v.1.7.5rc5 --cpus-per-proc is deprecated and is advised to
> replace by --map-by <obj>:PE=N.
> > I've tried this but I couldn't get the expected allocation of procs.
> >
> > For example I was running 2 procs on 2 nodes each with 2 sockets where
a
> socket has 4 cores. I wanted 1 proc per node and bound to all cores in
one
> of the sockets. I could get this by using
> >
> > --bind-to core: --map-by ppr:1:node --cpus-per-proc 4 -np 2
> >
> > Then it'll show bindings as
> >
> > [i51:32274] MCW rank 0 bound to socket 0[core 0[hwt 0]], socket 0[core
1
> [hwt 0]], socket 0[core 2[hwt 0]], socket 0[core 3[hwt 0]]:
> [B/B/B/B][./././.]
> > [i52:31765] MCW rank 1 bound to socket 0[core 0[hwt 0]], socket 0[core
1
> [hwt 0]], socket 0[core 2[hwt 0]], socket 0[core 3[hwt 0]]:
> [B/B/B/B][./././.]
> >
> >
> > Is there a better way without using -cpus-per-proc as suggested to get
> the same effect?
> >
> > Thank you,
> > Saliya
> >
> >
> >
> > --
> > Saliya Ekanayake esaliya_at_[hidden]
> > Cell 812-391-4914 Home 812-961-6383
> > http://saliya.org_______________________________________________
> > users mailing list
> > users_at_[hidden]http://www.open-mpi.org/mailman/listinfo.cgi/users
>
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>
> --
> Saliya Ekanayake esaliya_at_[hidden]
> Cell 812-391-4914 Home 812-961-6383
> http://saliya.org_______________________________________________
> users mailing list
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