[ale] high performance computing

[Jim Kinney]

With the high core count, narrow the cpu focus to the 16 core opterons.
On Jul 27, 2012 4:11 PM, "John Heim" <john at johnheim.net> wrote:

> From: "Jeff Layton" <laytonjb at att.net>
> To: "Atlanta Linux Enthusiasts" <ale at ale.org>
> >
> > The follow-up question is whether the FFT's are done locally
> > or if they are using an MPI based FFT?
> >
> > However, I think as a starting point, you'll want compute nodes
> > that have reasonably fast processors, lots of cache (as Jim
> > pointed out) but you also needs tons of memory BW per core.
> > FFT's love memory BW!!
> >
> > If the FFT's themselves are parallelized, then you will definitely
> > need InfiniBand. FFT's each networks for breakfast (in fact there
> > was a proposal from John Gustafson at Intel to make a 3D MPI
> > FFT the new benchmark for HPC since it pushed systems so
> > hard).
>
> I sent the PI your questions.  Here are his answers (somewhat abbreviated
> and w/o personal info).
>
> 1. 2D FFT's? 3D FFT's?
>
> Both.  Probably 3D more often then 2D.  But I am working on code right
> now that would always be 2code (never 3D).
>
> 2. Is the code parallelized via MPI or OpenMP or both?
>
> We have never bothered to explicitly parallelize our code.  We have been
> using the built-in parallelization in  calls to FFTW.
>
> 3. Is the code written with CUDA?
>
> No.
>
> 4. How many cores or processes are used per run?
>
> We need to have the capability to use at least 64 cores per run, maybe 128
> or 256 if possible within our budget.
>
> 5. Which compilers do you use or like?
>
> I think ifort is everybody's favorite.  I use the gnu g95 compiler
> sometimes, but I think it produces slower object modules than ifort.
>
> 6. How large are the input/output files?
>
> I create 10 Gb of output data from a serial run on my  desktop iMac
> (although it has typically been closer to 1 Gb per run since I have limited
> disk space here).  So if I had a big parallel run on 64 or more cores, I
> can
> imagine I could be creating 100 Gb of output
> data pretty  easily and maybe even 1 Tb or more.
>
> _______________________________________________
> Ale mailing list
> Ale at ale.org
> http://mail.ale.org/mailman/listinfo/ale
> See JOBS, ANNOUNCE and SCHOOLS lists at
> http://mail.ale.org/mailman/listinfo
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mail.ale.org/pipermail/ale/attachments/20120727/42c88b57/attachment.html