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Tree-based launch in Open MPI

I’ve mentioned it before: the run-time systems of MPI implementations are frequently unsung heroes.

A lot of blood, sweat, tears, and innovation goes into parallel run time systems, particularly those that can scale to very large systems.  But they’re  not discussed often, mainly because they’re not as sexy and ultra-low latency numbers, or other popular MPI benchmarks.

Here’s one cool thing that we added to the runtime in Open MPI a few years ago, and have continued to improve on over the years (including pretty pictures!).

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The “vader” shared memory transport in Open MPI: Now featuring 3 flavors of zero copy!

Today’s blog post is by Nathan Hjelm, a Research Scientist at Los Alamos National Laboratory, and a core developer on the Open MPI project.

The latest version of the “vader” shared memory Byte Transport Layer (BTL) in the upcoming Open MPI v1.8.4 release is bringing better small message latency and improved support for “zero-copy” transfers.

NOTE: “zero copy” in the term typically used, even though it really means “single copy” (copy the message from the sender to the receiver).  Think of it as “zero extra copies, i.e., one copy instead of two.”

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MPI over 40Gb Ethernet

Half-round-trip ping-pong latency may be the first metric that everyone looks at with MPI in HPC, but bandwidth is one of the next metrics examined.

40Gbps Ethernet has been available for switch-to-switch links for quite a while, and 40Gbps NICs are starting to make their way down to the host.

How does MPI perform with a 40Gbps NIC?

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Java Bindings for Open MPI

Today’s guest blog post is from Oscar Vega-Gisbert and Dr. Jose Roman from the Department of Information Systems and Computing at the Universitat Politècnica de València, Spain.

We provide an overview of how to use the Java bindings included in Open MPI. The aim is to expose MPI functionality to Java programmers with minimal performance penalties.

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New Open MPI stable series launched: v1.8

Open MPI logoThe Open MPI project released version v1.8 last week.  This is a major release that heralds the beginning of a new production-ready series, full MPI-3.0 support, and a new OpenSHMEM implementation.

Open MPI is developed in a tick-tock fashion:

  • Odd-numbered series are focused on feature development and expansion
  • Even-numbered series are focused on stability and production usage

The even-numbered v1.8.x series therefore represents a new production-ready series that effectively deprecates the prior production-ready series (v1.6.x).

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