gromacs benchmark and quad Xeons

David van der Spoel spoel at xray.bmc.uu.se
Wed Jun 19 12:30:36 EDT 2002


On Wed, 19 Jun 2002, Velocet wrote:

>we were seeing this:
>				   scaling vs 1cpu	  scaling vs 2cpu
>1 cpu   94 ps/day	94 / cpu	100% 			
>2 cpu  144 ps/day       72 / cpu	 77%			100%
>4 cpu  228 ps/day       57 / cpu         61%			 79%
>
>the scaling is about 75-80% of half as many cpus (per cpu). Quite odd. Im sure
>we must have something misconfigured, or, as you say, it could be that the
>memory bandwidth is being thrashed. 94 ps/day for a single cpu is already

did you set the --small-message options? (for shared memory and tcp)?
Don't recall full option, sorry

Groeten, David.
________________________________________________________________________
Dr. David van der Spoel, 	Biomedical center, Dept. of Biochemistry
Husargatan 3, Box 576,  	75123 Uppsala, Sweden
phone:	46 18 471 4205		fax: 46 18 511 755
spoel at xray.bmc.uu.se	spoel at gromacs.org   http://zorn.bmc.uu.se/~spoel
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