[gmx-users] cpu parallel

Mark Abraham Mark.Abraham at anu.edu.au
Tue Dec 2 14:51:31 CET 2008


ha salem wrote:
> Dear Users
> I have 2 computer,each mashine has 1 core2quad cpu.
> I have installed lamm 7,when I run mdrun -np4 on 1 machine cpu usage of 4 cores is over 90% and its s faster than single mode but when I run mdrun on 2 machines ,cpu usage of cores is about 30% and it doesnt get more speed
> can you help me?
> my network is gigabit and I connect 2 machines with gigbit cards and crooss cable

As you'll see if you search the GROMACS mailing list archives, gigabit 
is not normally good enough for acceptable scaling. Your processors are 
idling while waiting for data to transfer.

Mark



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