[Beowulf] MPI application benchmarks

[Toon Knapen]

Mark Hahn wrote:
>> Sigh. I thought I could avoid that response. Our own code (due to the no.
>> of users who all believe that their code is the most important and
>> therefore must be benchmarked) is so massive that any potential RFP
>> respondent would have to work a year to run the code. Thus, we have to
> 
> sure.  the suggestion is only useful if the cluster is dedicated to a 
> single purpose or two.  for anything else, I really think that 
> microbenchmarks are the only way to go.  after all, your code probably
> doesn't do anything which is truely unique, but rather is some 
> combination of a theoretical microbenchmark "basis set".  no, I don't
> know how to establish the factor weights, or whether this approach 
> really provides a good predictor.  but isn't it the obvious way,
> even the only tractable way?
> 


Agreed. On one hand you need micro-benchmark. OTOH you need your users 
to specify what are the sensitive points of their application. First of 
all, I suppose their applications are parallel, but are they BW-bound or 
latency-bound. How much time do the applications spend on communication? 
Are the app's capable of running in mixed-mode (MPI combined with 
multithreading), ...

Why do'nt you make a list of multiple-choice questions in a style as 
described above and ask your users to fill that in. This solves also the 
'weighting factor' because the users that respond to your question 
_care_ about the machine being suitable while the others care less.

t