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Hardware Locality 1.2.1 and 1.3rc1 released

August 23, 2011 at 4:27 am PST

In the vein of awesome software releases (ahem…), Hardware Locality (hwloc) v1.2.1 has been released.  As the “.1″ implies, this is a bug fix release of a bunch of little things that crept in the 1.2 series.  A full list of the news-worthy items can be found here.

But more awesome than that is the fact that Hwloc 1.3rc1 has also been released.  The Hwloc 1.3 series brings in some major new features.  The list of new features can be found below.

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Open MPI v1.5.4 released

August 22, 2011 at 8:45 am PST

We released Open MPI v1.5.4 last week.  Woo hoo!

I can’t exactly predict the future, but I anticipate having one more release before transitioning it to 1.6 (i.e., transitioning it from a “feature” release series to a “stable” release series where only bug fixes will be applied).

The v1.5 series is actually progressing quite nicely towards v1.6.  It has gotten a lot of run time on real-world machines in production environments, and many bugs have shaken out.  And there are many new, shiny toys on our development trunk that are slated for v1.7 (i.e., they won’t go into the v1.5/v1.6 series).

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The anatomy of MPI implementation optimizations

August 9, 2011 at 5:00 am PST

MPI implementations are large, complex beasts.  By definition, they span many different layers ranging from the user-level implementation all the way down to sending 1s and 0s across a physical network medium.

However, not all MPI implementations actually “own” the code at every level.  Consider: a TCP-based MPI implementation only “owns” the user-level middleware.  It cannot see or change anything in the TCP stack (or below).  Such an implementation is limited to optimizations at the user space level.

That being said, there certainly are many optimizations possible at the user level.  In fact, user space is probably where the largest number of optimizations are typically possible.  Indeed, nothing can save your MPI_BCAST performance if you’re using a lousy broadcast algorithm.

However, lower-layer optimizations are just as important, and can deliver many things that simply cannot be effected from user space.

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If not RDMA, then what?

August 6, 2011 at 7:30 am PST

In prior blog posts, I talked about some of the challenges that are associated with implementing MPI over RMA- or RDMA-based networks.  The natural question then becomes, “What’s the alternative?”

There’s at least two general classes of alternatives:

  • General purpose networks (e.g., Ethernet — perhaps using TCP/IP or even UDP)
  • Special purpose networks (i.e., built specifically for MPI)

This doesn’t even mention shared memory, but let’s return to shared memory as an MPI transport in a future post.

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Euro MPI 2011 Call for Pariticpation

July 22, 2011 at 5:00 am PST

WHAT: EuroMPI 2011 Conference
WHERE: Santorini, Greece
WHEN: September 18-21, 2011
URL: www.eurompi2011.org

BACKGROUND AND TOPICS

EuroMPI is the primary meeting where the users and developers of MPI and other message-passing programming environments can interact. The 18th European MPI Users’ Group Meeting will be a forum for the users and developers of MPI, but also welcome hybrid programing models that combine message passing with programming of modern architectures such as multi-core, or accelerators.

Through the presentation of contributed papers, poster presentations and invited talks, attendees will have the opportunity to share ideas and experiences to contribute to the improvement and furthering of message-passing and related parallel programming paradigms.

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