High Performance Computing Networking

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MPI newbie: Building MPI applications

In a previous post, I gave some (very) general requirements for how to setup / install an MPI installation. This is post #2 in the series: now that you’ve got a shiny new computational cluster, and you’ve got one or more MPI implementations installed, I’ll talk about how to build, compile, and link applications that […]

October 12, 2013 4 min read
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EuroMPI’13 Cisco slides: Open MPI Process Affinity User Interface

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 […]

September 18, 2013 1 min read
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Short message latency and NUMA effects

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 […]

July 23, 2013 2 min read