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From: Gaurav Jain (gaurav_at_[hidden])
Date: 2003-06-14 13:22:05


Hi all,

I am tried to built a 8-node cluster with following configs

Dual-cpu Intel Xeon 2.6 GHz (hyperthreading disabled)
1 GB RAM
100 Mbps LAN

and

RedHat Linux 8.0 with kernel 2.4.20 (with OpenMosix patch)
LAM-MPI 6.5.9
ATLAS

When I run HPL (www.netlib.org/benchmark/hpl) with N=(5000-25000) and
different combinations of options,
over 1 cpu(with SMP disabled), I get peak performance of 1.58 GFlops
(N=8000, NB=128)
over 2 cpu(with smp enabled), I get peak performance of 2.85 GFlops
(N=10000, NB=128)
over 16 cpu(8-node cluster), I get peak performance of 9.64 GFlops
(N=10000, NB=128)

As I understand it,
with one CPU, the peak performance is 2.6 GHz * 2 = 5.2 GFlops
with one node, the peak performance is 2.6 GHz * 2 * 2 = 10.4 GFlops
with eight nodes, the peak performance is 2.6 GHz * 2 * 2 * 8 = 83.2 GFlops

But, I am getting only 11% of peak performance. Any pointers, what I may be
doing wrong?

Regards,
Gaurav Jain