Open MPI logo

Hardware Locality Users' Mailing List Archives

  |   Home   |   Support   |   FAQ   |   all Hardware Locality Users mailing list

Subject: Re: [hwloc-users] Re : lstopo on multiple machines
From: Marcelo Alaniz (malaniz_at_[hidden])
Date: 2011-08-16 15:53:49


-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On Tue, Aug 16, 2011 at 07:59:46PM +0200, Brice Goglin wrote:
> Marcelo,
>
Brice, first, thanks for this amazing library.
The responses are below.

> Could you describe a bit more what you would like to see? What we're
> thinking of doing is having something like:
>
> System #0
> Machine #0
> Socket #0
> ...
> Machine #1
> ...
>
>
> If people discover the network topology too (for instance the hierarchy
> of switches), we could even have
>
> System #0
> Group0 #0
> Group1 #0
> Machine #0
> ...
> Machine #4
> Group1 #1
> Machine #1
> Machine #3
> Group0 #1
> Group1 #2
> Machine #2
> ...
> Machine #7
> Group1 #3
> Machine #5
> Machine #6
>
The problem that i'm trying to resolve it's mapping of cellular
automata in a cluster multicores.
The second representation is great if i have the speed of the
channels, like group1 (1 hop), group0 (2 hops) in a piramid of access.
Like as type of cache between cores.

That's because the mainly problem is grouping more communicated tasks
in the faster communication channels.
For example, if i have a task0 more communicated with task2 and
task3, but less communicated with task1, then i'll try to put the
task0, task2 and task3 on some places (core, thread or machine) with
faster channel than task1.
>
> Second question. How would like this topology to be built? We could have
> something like this in the API:
>
> /* create a topology with only a System object root */
> hwloc_topology_create_empty()
>
> /* load a XML topology and insert it below a given object */
> hwloc_topology_insert_xml_by_parent()
>
> A new utility would use these to agregate multiple XML topologies. You
> would have to run lstopo foo.xml on each node and run this new utility
> to create the global XML topology. Finally, you can run hwloc with the
> new global topology and do whatever you want.
For my that's fine. Mainly because i will run this on one
cluster and in a static form. I.e., before the work horse to resolve
the CA problem, i will autodiscover the architecture of the cluster
and then will map the tasks in threads, cores and nodes.

But, for other problems, like tunning on GRIDs maybe you need severals
Systems ...

Best!
Marcelo.

>
> Brice
>
>
>
> Le 16/08/2011 16:27, Marcelo Alaniz a écrit :
> > -----BEGIN PGP SIGNED MESSAGE-----
> > Hash: SHA1
> >
> > Hi Brice,
> > I'm a PhD Student in Argentina (SouthAmerica). Now, i'm focus on
> > hybrid computing and mapping technics for clusters multicore.
> >
> > i'm using hwloc to discover the nodes architecture ... the multinode
> > topology detection will be great for me! because i will try to make
> > that in the nearless future.
> >
> > Cheers!
> > Marcelo
>
> _______________________________________________
> hwloc-users mailing list
> hwloc-users_at_[hidden]
> http://www.open-mpi.org/mailman/listinfo.cgi/hwloc-users

- --
Degree Alaniz Marcelo
Frontend Development
HPC PhD Student
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.11 (GNU/Linux)

iEYEARECAAYFAk5Kys0ACgkQ0bw3ME61/hIlhACeOmybpdZ9F85rUAy3YuDIC5Ss
mecAn2I0BIfWJhDGJv84BunN38K67V92
=heGT
-----END PGP SIGNATURE-----