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Open MPI: Binding to core by default

December 18, 2013 at 12:55 pm PST

After years of discussion, the upcoming release of Open MPI 1.7.4 will change how processes are laid out (“mapped”) and bound by default.  Here’s the specifics:

  • If the number of processes is <= 2, processes will be mapped by core
  • If the number of processes is > 2, processes will be mapped by socket
  • Processes will be bound to core
  • MPI_COMM_WORLD ranks will be assigned by slot

These are all the default values — they, of course, can be changed by the user via mpirun CLI options, environment variables, etc.

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10 Years of Open MPI

November 22, 2013 at 5:00 am PST

Today’s the day.

Today marks 10 years since the first commit in the original Open MPI CVS source code repository (which was later converted to Subversion):

$ svn log -r 1 http://svn.open-mpi.org/svn/ompi
------------------------------------------------------------
r1 | jsquyres | 2003-11-22 11:36:58 -0500 (Sat, 22 Nov 2003)
First commit
------------------------------------------------------------

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The Network Locality Project (netloc)

November 18, 2013 at 5:00 am PST

Today’s guest post comes from Dr. Joshua Hursey, an Assistant Professor in the Computer Science Department at the University of Wisconsin, La Crosse.

For a number of years, developers tuning High Performance Computing (HPC) applications and libraries have been harnessing server topology information to significantly optimize performance on servers with increasingly complex memory hierarchies and increasing core counts.  Tools such as the Portable Hardware Locality (hwloc) project provide these applications with abstract, yet detailed, information of the single-server topology.  But that is where the topology analysis often stops — neglecting the one of the largest components of the HPC environment, namely: the network.

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At SC’13 next week? Come say hi!

November 13, 2013 at 2:54 pm PST

sc13-logo_0Are you going to be in Denver at SC’13 next week?

Good!

You need to stop by the Cisco booth (#2535) and say hi to your friendly neighborhood Open MPI developers: Dave Goodell, Reese Faucette, and Jeff Squyres.

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Lawrence Berkeley Labs talk: Cisco Userspace NIC (usNIC)

November 8, 2013 at 11:58 am PST

Here’s the slides from my second talk, which is a deep technical dive into both how the usNIC technology works, and how we use that technology in the BTL plugin that we wrote for Open MPI (which is upstream starting with Open MPI v1.7.3).

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