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Lawrence Berkeley Labs talk: (Open) MPI, Parallel Computing, Life, the Universe, and Everything

November 8, 2013 at 11:57 am PST

Many thanks to the crew at LBL for hosting my talks yesterday.  There were many insightful questions and comments throughout both talks.

Here’s the slides from my first talk, entitled “(Open) MPI, Parallel Computing, Life, the Universe, and Everything.”  This is a general MPI/Open MPI talk, where I discussed the current state of Open MPI, and then talked in detail about two of Open MPI’s newest features: the MPI-3 “MPI_T” tools interface, and Open MPI’s flexible process affinity system.

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My new favorite Open MPI mpirun feature: tab completion

November 1, 2013 at 5:00 am PST

Today’s guest author is Nathan Hjelm, a Scientist 2 at Los Alamos National Laboratory.

We recently added scripts to support tab completion of mpirun flags and run-time MCA configuration variables to the Open MPI trunk development. The scripts support both bash and zsh and have a number of useful features (depending on the shell).

Can’t remember how to spell that MCA parameter name? Just hit <TAB>.
Can’t remember which transports are available? Just hit <TAB>.
Can’t remember the name of that mpirun CLI option? Just hit <TAB>.

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Speaking at Lawrence Berkeley National Lab next week

October 30, 2013 at 9:45 am PST

Are you in the Northern California Bay Area and want to hear about Open MPI and/or Cisco’s usNIC technology next week?

If so, you’re in luck!

I’ll be speaking at Lawrence Berkeley Lab (LBL) next Thursday, November 7, 2013, at 2:30pm.  Click through to see the location and directions and whatnot (LBL requests that you RSVP if you plan to attend).

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EuroMPI’13 Cisco slides: Open MPI Process Affinity User Interface

September 18, 2013 at 5:17 am PST

The slides below are from my presentation at EuroMPI’13 about Open MPI’s flexible process affinity interface (in OMPI 1.7.2 and later).  I described this system in a prior blog entries (one, two, three), but many people keep asking me about it.

Josh Hursey from U. Wisconsin, LaCrosse, wrote this IMUDI paper about the interface (IMUDI is a sub-workshop of EuroMPI focusing on end-user issues) to get a little more publicity and awareness of this process affinity system.  Specifically, we designed this affinity system so that we could get feedback from real end users about what is useful and what is not.

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Short message latency and NUMA effects

July 23, 2013 at 5:00 am PST

I’ve previously written a bunch about the effects of location, Location, LOCATION! on MPI applications.

Here’s another subtle NUMA effect that a well-tuned MPI implementation can hide from you: intelligently distributing traffic between multiple network interfaces.

Yeah, yeah, most MPI implementations have had so-called “multi-rail” support for a long time (i.e., using multiple network interfaces for MPI traffic).  But there’s more to it than that.

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