CPU usage percentage in MPI applications

Question

I used MPICH2. When I start my applications by using mpiexec, they run on the remote hosts (Win7) have 25% CPU usage. I want to increase the percentage if this can improve my application performance. I wish that my remote computers are dedicated to my calculations. How can I do?

Thanks

Let me guess: remote host use quad-core processors, but run only one instance of MPI node? — GreyCat, Sep 10 '11 at 06:52
I guess that I should have known these points before starting to work on MPI. — adba, Sep 10 '11 at 07:41

score 5 · Accepted Answer · answered Sep 10 '11 at 07:05

For MPI processes your # of processes should match the sum of the core count of your machines (assuming a CPU-heavy workload). If an MPI process runs with -np 4 on a quad-core box, it will consume all four cores and you'll see your CPU usage near 100%. If it runs with -np 1 the CPU load of the box is going to be around 25% (because only one core out of four is dedicated to your calculations). Any additional increase and they will start to contend for CPU time.

CPU usage percentage in MPI applications

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