[Beowulf] Strange Behavior

Lars Henriksen lars at meshtechnologies.com
Fri Mar 12 11:43:47 EST 2004

On Fri, 2004-03-12 at 13:51, Mathias Brito wrote:

> I'm benchmarking my 16 nodes cluster with HPL and I
> obtain a estrange result, different of all I ever seen
> before. When I send more data with a big N, the
> performance is worse than with small values of N. I
> used N=5000 with NB=20 and the performance was 3.3GB,
> when I send N=10000 with NB=20 i get only 2.1GB. I
> don't liked the result, the nodes are athlon xp 1600+
> with 512MB RAM, and I think the cluster very slow.
> Someone had the same problem and could help me?

Please correct me anybody, if im wrong:
It seems to me, that the best results are acheived with approx 85-90%
memory utilization (leaving something to the rest of the system).

(16*512*1024*1024/8)^0.5 ~= 30200, that would close to the best N value
isn't Nb=20 very low? I currently use arround 145 for P4 cpu's

What performance du you get from a setup like the one above?

best regards

Lars Henriksen                  | MESH-Technologies A/S
Systems Manager & Consultant    | Lille Graabroedrestraede 1
www.meshtechnologies.com        | DK-5000 Odense C, Denmark
lars at meshtechnologies.com       | mobile: +45 2291 2904
direct: +45 6311 1187	 	| fax:	  +45 6311 1189

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