[Beowulf] MPI application benchmarks

[Bill Rankin]

Toon Knapen wrote:
> Mark Hahn wrote:
>> 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.

I'm not sure that I agree with this - there are just so many  
different micro benchmarks that I would worry that relying upon them  
for anything other than basic system validation (which they are very  
good at) leaves the potential for some very big holes in your  
requirements.  Especially in a general purpose system like the one  
proposed.


> Why don't 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.


This is an excellent idea.  Even with 1000's of users, you still need  
to understand the mix of application types you will see.  Then you  
can make some informed judgments on the overall system architecture.   
Some questions that you will need to consider:

- What is the "experience level" of your audience. ?
- Are they writing their own MPI or pthreads code?  Or are they just  
using canned apps?  What apps and how do you handle licenses?
- Do you have a significant population who are looking to do larger  
scale (100+ process) MPI jobs?  Is it worth the expense to invest in  
high-speed interconnects, or is GigE sufficient?
- Pay attention to the storage system, both in scale and  
performance.  It's often both a hidden bottleneck and a single point  
of failure.
- Do you have users who want to toss around Terabytes off data?
- How do you plan on backing up these Terabytes of data?

These are just a few off the top of my head.  There are more.  But I  
think that a quick fairly simple survey will be invaluable towards  
planning this facility.

Good luck,

-bill