Open MPI logo

Open MPI User's Mailing List Archives

  |   Home   |   Support   |   FAQ   |   all Open MPI User's mailing list

Subject: Re: [OMPI users] How to replace --cpus-per-proc by --map-by
From: Saliya Ekanayake (esaliya_at_[hidden])
Date: 2014-03-27 11:38:49


Thank you, this is really helpful.

Saliya

On Thu, Mar 27, 2014 at 5:11 AM, <tmishima_at_[hidden]> wrote:

>
>
> 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
> >
> > _______________________________________________
> > users mailing list
> > users_at_[hidden]
> > http://www.open-mpi.org/mailman/listinfo.cgi/users
> >
> >
> >
> > --
> > 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
>
> _______________________________________________
> users mailing list
> users_at_[hidden]
> http://www.open-mpi.org/mailman/listinfo.cgi/users
>

-- 
Saliya Ekanayake esaliya_at_[hidden]
Cell 812-391-4914 Home 812-961-6383
http://saliya.org