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Subject: [OMPI users] Problems in OpenMPI
From: Yin Feng (yfeng1_at_[hidden])
Date: 2009-07-10 00:40:32


I am a beginner in MPI.

I ran an example code using OpenMPI and it seems work.
And then I tried a parallel example in PETSc tutorials folder (ex5).

mpirun -np 4 ex5
It can do but the results are not as accurate as just running ex5.
Is that thing normal?

After that, send this job to supercomputer which allocates me 4 nodes
and each node has 8 processors. When I check load on each node, I
found:
Node LOAD CPU
0 32 800
1 0 0
2 0 0
3 0 0

But for other's job, they got
Node LOAD
0 8
1 8
2 8
3 8

It seems the master node take all the load and the speed is even lower
than it works on single processor.

Does anyone have any idea about this?

Thank you in advance!

Sincerely,
YIN