[Beowulf] Stroustrup regarding multicore
Peter St. John
peter.st.john at gmail.com
Wed Sep 3 10:34:49 PDT 2008
I'm thinking that multicore will make topology interesting again, because of
the difference between intercore on a common chip vs going through a nic to
even the fastest fabric.
On 9/3/08, Lux, James P <james.p.lux at jpl.nasa.gov> wrote:
> I would say that the single biggest problem in HPC today is not getting
> sufficient hardware horsepower, but in effectively using that power. 10
> years ago, just getting a cluster going was a bit of a challenge, in terms
> of knowing what hardware to get, how to interconnect it, etc, but now, a
> of that is cookbook (or available turnkey from a variety of vendors... A
> very different matter from when Sterling, et al wrote their book back in
> 98/99). Sure, there are still hardware issues that are worthy of discussion
> on this list (details of interconnects, etc.), but one doesn¹t see the
> discussions about topologies that one saw back then. The hardware is now
> the point where you rack up the computers, hook them all to a very fast
> switch with huge bisection bandwidth, and you¹re done.
> However, the topic of taking a simple problem and effectively parallelizing
> it (either at a EP level as can be done with some Monte Carlo or systematic
> simulations, or at a fine grained level, as with matrix numerical modeling)
> is very much grist for the mill.
> After all, what are all those folks building parallelizing/vectorizing
> compilers trying to do but reduce the substantial software
> engineering/design problem, so that a scientist or engineer can just write
> their problem out in simple form, and have ³the backend² figure out how to
> do it efficiently (or at all).
> There are many problems which are, by their nature, software design complex
> enough that it is not reasonable to have the person ³asking the question²
> also be knowledgeable enough to manage the substantial software development
> project. This would be true, if for no other reason than managing a
> development effort takes a different skill set than asking good science or
> engineering questions.
> So, the real challenge facing builders (in the larger sense) of Beowulfs is
> in developing methods to get the work actually done, and if that requires
> developing skills in ³eliciting requirements² or, more probably,
> ³communicating between software speak and science speak², then this is an
> appropriate place to do it (if not here, then where *would* be a place
> it¹s more germane.. I can't think of one off hand)
> It's sort of like our discussions about communicating with the facilities
> folks about power requirements or HVAC. Someone building a cluster needs
> know something about this to be an intelligent consumer, but nobody expects
> the scientist to be down there sweating copper pipes for the chiller or
> cabling up the EPO button for the UPS.
> The list is valuable because there *are* folks here who do know how to
> pipes, manage software projects, and interpret the electrical code, and you
> can ask a question about such things and get a host of responses, some more
> useful than others.
> On 9/3/08 9:10 AM, "Prentice Bisbal" <prentice at ias.edu> wrote:
> > This discussion is still completely off-topic. This is a list about
> > computing issues relating to beowulf clusters, not software engineering
> > at large, sociology or psychology.
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