Do you know what an iBarrier is?

1. A joke in the MPI Forum
2. A useful synchronization technique
3. Waiting in line at the Apple store for an iPhone

For a long time, the answer was #1 — we jokingly referred to “non-blocking barriers” in the same breath as MPI_SEND_ANY and MPI_ESP(do_what_i_meant_not_what_i_coded).  But recently, the answer has become #2.

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Lots of interesting things were announced at the International Supercomputing Conference (ISC’10) this week.  Sadly, I wasn’t there; I was just reading the press releases, tweets, blogs, and watching the vlogs like everyone else who wasn’t there.

I’ll pick just one topic to discuss here: the Intel Many Integrated Cores (MIC) announcement.

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Sorry folks — Brock and I got caught up in our day jobs recently, and didn’t get to put out an RCE podcast this week.

We have some more interviews on tap, so stay tuned.  We’ll return to our regularly-scheduled every-two-weeks publication in two weeks.

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…except when it isn’t.

Most people throw around latency and bandwidth numbers as the most important metrics for a given MPI implementation.  “MPI implementation X is terrible because MPI implementation Y’s latency is 5% lower!”

Ahh… the fervence of youth (and marketing).  If only the world was so black and white.  But it’s not.  The world is grey.  I can think of 20 metrics and implementation features off the top of my head that matter to real-world users and applications.

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Let’s revisit my stats from a prior blog post about who uses the MPI C++ bindings.  Jed Brown was kind enough to school me in how terrible my prior statistical analysis was.  

I’ve actually removed the offending stats from that entry and am re-doing them here; hopefully in a more meaningful way.  I won’t even describe how bad / wrong my prior analysis was; let’s just go through the numbers again with a little something I like to call The Right Way…

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