MPI-3

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Overlap of communication and computation (part 2)

In part 1 of this series, I discussed various peer-wise technologies and techniques that MPI implementations typically use for communication / computation overlap. MPI-3.0, published in 2012, forced a change in the overlap game. Specifically: most prior overlap work had been in the area of individual messages between a pair of peers.  These were very […]

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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. The 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 […]

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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 […]

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Open MPI and the MPI-3 MPI_T interface

Open MPI recently revamped its entire run-time parameter system (a.k.a., “MCA parameter system”) as part of its implementation effort for the “MPI_T” interface from MPI-3. The MPI_T interface is a standardized interface designed for MPI tools, but can be used by regular MPI application programs, too. Specifically, MPI_T provides programatic access to two types of […]

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MPI-3 standard available in hardcover

The MPI-3.0 standard is now available in hardcover (it’s green!).  The book is available for cost by Dr. Rolf Rabenseifner at HLRS; no profit is being made by these sales.  Here’s an excerpt from Rolf’s original announcement: As a service (at costs) for users of the Message Passing Interface,  HLRS has printed the new Standard, […]