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Why MPI is Good for You (part 3)

I’ve previously posted on “Why MPI is Good for You” (blog tag: why-mpi-is-good-for-you).  The short version is that it hides the typical application programmer from lots and lots of underlying network stuff; stuff that they really, really don’t want to be involved in.

Here’s another case study…

Cisco’s upcoming ultra-low latency MPI transport is implemented over an “unreliable” transport: raw Ethernet L2 frames. For latency reasons, it’s using the OpenFabrics verbs operating-system bypass API. These two facts mean that a) userspace is directly talking to the NIC hardware, and b) we don’t have a driver thread running down in the kernel that can service incoming frames regardless of what the MPI application is doing.

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The History and Development of the MPI standard

Today’s guest posting comes from Jesper Larsson Träff; he’s Faculty of Informatics, Institute of Information Systems in the Research Group for Parallel Computing at the Vienna University of Technology (TU Wien).

Have you ever wondered why MPI is designed the way that it is?  The slides below are from Jesper’s talk about the History and Development of the MPI standard.  They go into detail about how certain design decisions were made, and why.  Amusingly, I’m in a picture on slide 2.  :-)

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MPI Quiz

A fun scenario was proposed in the MPI Forum today.  What do you think this code will do?

MPI_Comm comm, save;
MPI_Request req;
MPI_Comm_dup(MPI_COMM_WORLD, &comm);
MPI_Comm_rank(comm, &rank);
save = comm;
MPI_Isend(smsg, 4194304, MPI_CHAR, rank, 123, comm, &req);
MPI_Recv(rmsg, 4194304, MPI_CHAR, rank, 123, save, MPI_STATUS_IGNORE);

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Cisco’s Philosophy on Open Source

Last weekend, I was fortunate enough to be able to attend the Midwest Open Source Software Conference (MOSSCon 2013).  I met some fascinating people, listened to some great talks, and learned a bunch of new things.

All in all, a win.

I also presented a talk on two things:

  1. The general open source philosophy at Cisco
  2. My specific open source work at Cisco

The slides that I presented are below (slightly edited from their original form; I used a few animations in my original slides, which don’t work on Slideshare):
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Speaking about Open MPI / FOSS at Midwest Open Source Convention this weekend

I’ve been a bit remiss about posting recently; it’s conference-paper-writing season, folks — sorry.

But I thought I’d mention that I’ll be speaking at the Midwest Open Source Software Convention (MOSSCon) this weekend.

I’ll be talking about my work in Open MPI, Hardware Locality (hwloc), and other open source projects, as well as Cisco’s role in open source communities.  To be honest, when I joined Cisco (7 years ago… where has the time gone?), the fact that I could keep working in the open source community was one of the major factors in my decision to come here.

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