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Open MPI v1.5 (and v1.4.3) released!

October 11, 2010 at 8:00 am PST

Open MPI logoRepresenting over a year of research, development, and testing, the Open MPI team is extremely pleased to release version v1.5.  Read the full announcement here.  Version 1.5 is chock full of new features and countless little enhancements.  We hope you’ll enjoy it!

Open MPI Version v1.4.3 was just released a few days ago, too.   It’s mainly a bug fix release that increases the stability of the time-tested v1.4 series.

Some of you may be wondering, “Why the heck would they put out a point release and then a major new revision within a few days of each other?”

How fortunate that you ask!  Let me explain…

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MPI concepts that didn’t make it

October 8, 2010 at 5:00 am PST
The following is an abbreviated list of my favorite concepts and/or specific functions that never made the cut into an official version of the MPI specification:
  • MPI_ESP(): The “do what I meant, not what my code says” function.  The function is intended as a hint to the MPI implementation that the executing code is likely incorrect, and the implementation should do whatever it feels that the programmer really intended it to do.
  • MPI_Encourage(): A watered-down version of MPI_Progress().
  • MPI_Alltoalltoall(): Every process sends to every other process, and then, just to be sure, everyone sends to everyone else again.  Good for benchmarks. Read More »

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New blog site!

October 4, 2010 at 5:58 pm PST

Just a digression from the normal technical talk here…  We finally launched the new Cisco blogs site.  Woo hoo!!

Most importantly, I wanted to let you all know that the landing page and RSS feed URLs have both changed.  There are HTTP redirects in place for both (which I noticed this morning caused a bunch of old RSS entries to be marked as “new” — oops), but just in case you need to know them:

You don’t need to update your bookmarks / RSS readers, but you might want to anyway just because all the cool kids are doing it.

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“Give me 4 255-sided die and I’ll get you some IPs”

September 29, 2010 at 12:00 pm PST

Have you ever wondered how an MPI implementation picks network paths and allocates resources?  It’s a pretty complicated (set of) issue(s), actually.

An MPI implementation must tread the fine line between performance and resource consumption.  If the implementation chooses poorly, it risks poor performance and/or the wrath of the user.  If the implementation chooses well, users won’t notice at all — they silently enjoy good performance.

It’s a thankless job, but someone’s got to do it.  :-)

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Process-to-process copy in Linux

September 16, 2010 at 12:00 pm PST

More exciting news on the Linux kernel front (thanks for the heads-up, Brice!): our friends at Big Blue have contributed a patch and started good conversation on the LKML mailing list about process-to-process copying.  We still don’t have a good solution for being notified when registered memory is freed (my last post on this topic mentioned that the ummunotify patch had hit the -mm tree, but that eventually didn’t make it up to Linus’ tree), but hey — this is progress, too (albeit in a slightly different direction), so I’ll take it!

“Why do I care?” you say.

I’m glad you asked.  Let me explain…

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