[Beowulf] GP-GPU experience

Lux, Jim (337C) james.p.lux at jpl.nasa.gov
Mon Apr 4 09:53:22 PDT 2011

You've described it pretty well..

Look how long it took for "standard libraries" to take advantage of things like MPI to become "of course we use that"..

If the original code used standard library calls for things like matrix math, and it's a "drop in" so you could do a "test case" in less than a day or so, you get pretty rapid acceptance.  If it requires weeks to just figure out how to make it work, it's going to be in the "when someone specifically funds me to do it".  

I've seen lots of really interesting things that I'd like to try, but not being independently wealthy or having a patron who is, I have to work on things that other people want done (and, presumably which I also find interesting).  I can write proposals to say "it would be really nice to do X because of speculative benefit Y"  and every once in a while, someone will say, "Yeah, that sounds good, go check it out".  And then we do.  

But it's a long and time consuming process.  For instance, I was just in a presentation last week discussing a recent call for proposals from NASA.. the *shortest* time from proposal to response (yes/no) was around 120 days, the median was around 200 days, and the max was around 400 days plus, depending on the year.

A lot depends on what happens to the budgets as they wend their leisurely way through the program offices at the agencies, then get rolled up in the President's submission, then thrashed in Congress, then allocated, then back through the agency, and finally back down to the program.  To provide some perspective on the front end of the process, the program managers at the agencies are winding up their PPBE13 submissions (that's for FY13, starting October 2012, although it also affects FY12 funding) 

A "new technology" that hasn't been "on the radar" probably has a 2-3 year lag before significant money can be applied to it (at least from government funding sources).  Often, one can get smaller sums more quickly out of some general "investigate new technologies" kind of bucket (smaller sums = a few $10k), but right now, even those have essentially dried up  (Continuing resolutions, etc.)

To tie this back to the first question.. a few $10k would pay for the "Lets try recompiling with the new library and see if it works" sort of level of effort, but not for a "Let's rewrite our codes for the new hardware, and engage in a validation and verification effort to show that it still works"

James Lux, P.E.
Co-Principal Investigator, CoNNeCT Project
Task Manager, SOMD Software Defined Radios
Flight Communications Systems Section
Jet Propulsion Laboratory
4800 Oak Grove Drive, Mail Stop 161-213
Pasadena, CA, 91109
+1(818)354-2075 phone
+1(818)393-6875 fax 
> -----Original Message-----
> From: beowulf-bounces at beowulf.org [mailto:beowulf-bounces at beowulf.org] On Behalf Of Herbert Fruchtl
> Sent: Monday, April 04, 2011 8:16 AM
> To: beowulf at beowulf.org
> Subject: Re: [Beowulf] GP-GPU experience
> They hear great success stories (which in reality are often prototype
> implementations that do one carefully chosen benchmark well), then look at the
> API, look at their existing code, and postpone the start of their project until
> they have six months spare time for it. And we know when that is.
> The current approach with more or less vendor specific libraries (be they "open"
> or not) limits the uptake of GPU computing to a few hardcore developers of
> experimental codes who don't mind rewriting their code every two years. It won't
> become mainstream until we have a compiler that turns standard Fortran (or C++,
> if it has to be) into GPU code. Anything that requires more change than let's
> say OpenMP directives is doomed, and rightly so.
>    Herbert
> >
> > I've installed 4 GPU-equipped servers in my environment; 2 are a part of
> > my cluster, and 2 are independent from the cluster so that users can
> > login interactively and program/debug/tinker/whatever. (My cluster
> > doesn't allow interactive logins by design).
> >
> > A handful of users were interested in getting access to the GPUs, but so
> > far, not a single one has even logged into these systems to kick the
> > tires yet, and the systems have been online for approx. 9 months. It
> > just be that they're busy with other work. Most of my users are
> > post-docs who guide their own research, so they can create/modify their
> > own project schedules as they see fit.
> >
> >
> --
> Herbert Fruchtl
> Senior Scientific Computing Officer
> School of Chemistry, School of Mathematics and Statistics
> University of St Andrews
> --
> The University of St Andrews is a charity registered in Scotland:
> No SC013532
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