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

May 17, 2014 at 5:13 am PST

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

May 10, 2014 at 3:29 am PST

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

April 30, 2014 at 12:10 pm PST

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

April 11, 2014 at 9:00 am PST

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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Belated April Fool’s blog post

April 11, 2014 at 6:47 am PST

MPIoEI was on vacation last week, and had a nice April Fool’s blog post queued up to be posted at 8am US Eastern time on 1 April 2014.

It should have appeared whilst I was relaxing on a beach… but due to a bug in our WordPress installation, it didn’t.  And I didn’t find out about the error until after I returned from vacation (long after April 1st).

Sad panda.

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