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Don’t leak MPI_Requests

December 22, 2012 at 8:02 am PST

With the Mayan apocalypse safely behind us, now we can now safely discuss MPI again.

An MPI application developer came to me the other day with a potential bug in Open MPI: he noticed that Open MPI was consuming vast amounts of memory such that trying to allocate memory from his application failed.  Ouch!

It turns out, however, that the real problem was that he was never completing his MPI_Requests.  He would start non-blocking sends and receives, but then he would use some other mechanism to “know” that those sends and receives had completed.

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McMPI

December 10, 2012 at 8:08 am PST

Today’s guest blog entry comes from Daniel Holmes, an Applications Developers at the EPCC

I met Jeff at EuroMPI in September, and he has invited me to write a few words on my experience of developing an MPI library.

My PhD involved building a message passing library using C#; not accessing an existing MPI library from C# code but creating a brand new MPI library written entirely in pure C#. The result is McMPI (Managed-code MPI), which is compliant with MPI-1 – as far as it can be given that there are no language bindings for C# in the MPI Standard. It also has reasonably good performance in micro-benchmarks for latency and bandwidth both in shared-memory and distributed-memory.

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EuroMPI 2013: CFP

November 30, 2012 at 6:07 pm PST

It’s that time of year again — time to start preparing for Euro MPI 2013!

Next year, we’ll be heading to Madrid, Spain September 15-18.   Here’s a snipit from the call for papers:

Topics of interest include, but are not limited to:

  • MPI implementation issues and improvements
  • Extensions to and shortcomings of MPI
  • Tools and environments for MPI
  • Hybrid and heterogeneous programming with MPI and other interfaces

Come join us for some sangria in scenic Madrid next year.  Submission deadline is March 29th.

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Cisco ultra low latency support for MPI

November 16, 2012 at 9:42 am PST

My team demonstrated our new ultra-low latency Ethernet solution in the Cisco booth at SC this past week (it was so busy that I didn’t get to post this until it was all over!).

The short version is that we have implemented operating system bypass and NIC hardware offload via the Linux OpenFabrics verbs API stack. We call it “userspace NIC”, or “USNIC”.

But let’s cut to the chase — what’s the performance?  Let’s break it down:

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MPICH 3.0 RC released

November 14, 2012 at 6:16 am PST

The MPICH folks have released an RC candidate for MPICH 3.0:

A new preview release of MPICH, 3.0rc1, is now available for download. The primary focus of this release is to provide full support for the MPI-3 standard.  Other smaller features including support for ARM v7 native atomics are also included.

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