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First public tools for the MPI_T interface in MPI-3.0

Today’s guest post is written by Tanzima Islam, Post Doctoral Researcher at Lawrence Livermore Laboratory, and Kathryn Mohror and Martin Schulz, Computer Scientists at Lawrence Livermore Laboratory.

MPI_T logoThe latest version of the MPI Standard, MPI 3.0, includes a new interface for tools: the MPI Tools Information Interface, or “MPI_T”.

MPI_T complements the existing MPI profiling interface, PMPI, and offers access to both internal performance information as well as runtime settings. It is based on the concept of typed variables that can be queried, read, and set through the MPI_T API.

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Can I MPI_SEND (and MPI_RECV) with a count larger than 2 billion?

This question is inspired by the fact that the “count” parameter to MPI_SEND and MPI_RECV (and friends) is an “int” in C, which is typically a signed 4-byte integer, meaning that its largest positive value is 231, or about 2 billion.

However, this is the wrong question.

The right question is: can MPI send and receive messages with more than 2 billion elements?

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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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