xdlutime results

Patrick GEOFFRAY pgeoffra at lhpca.univ-lyon1.fr
Tue Sep 12 22:56:38 EDT 2000

Putchong Uthayopas wrote:

> Below are our results. The machines is 8 Athlon 550MHz and one 1Ghz Athlon.
> 512 Mb memory each. and Myrinet.

> WALL 6000 9 1 9 116.80 0.41 1229.04 0.001097 PASSED
> WALL 6000 9 9 1 200.79 3.65 704.66 0.001926 PASSED


it seems that you are far from what you can get from your cluster
* First, 9 nodes is not a good idea, the (1*9) or (9*1) grids are
bad. you should use only 8 nodes and try (2*4) and (4*2) grids,
much better.
* Then 6000 is not a big matrix. If you have 512 MB per node, you
should go up to 20000. It will run longuer but you will be closest
to the peak.
* Which Blas do you use ? Atlas gives a DGEMM peak at 600 MFlops
per Athlon, so you can hope about 4 GFlops on your cluster.
* Which MPI do you use ? if it's MPICH-GM, do you use the
-gm-can-register-memory flag ?

I strongly advice you to use the new High Performance Linpack
(HPL) benchmark form Antoine Petitet
(http://www.netlib.org/benchmark/index.html), it's faster than the
old Linpack and much easier to install.

Hope it can help.

Patrick Geoffray
Aerospatiale Matra - Sycomore
Universite Lyon I - RESAM

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