CPU usage problem with mpich2 and lammps

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1

Dear users,

I’ve got a problem that running lammpswith mpirun causes abnormal CPU usage.
I compiled and installed succesfully the latest version of Lammps from the website,
with the latest mpich2. However when running mpirun -np X lmp < in.file , it seems
that whatever X is, almost all the 8 cores are fully used. When running only
lmp < in.file without mpirun, CPU usage is around 12.5% which is normal.

Any suggestions about this problem?

Best regards,
Fan Du

2

Dear users,

I've got a problem that running lammpswith mpirun causes abnormal CPU usage.
I compiled and installed succesfully the latest version of Lammps from the
website,
with the latest mpich2. However when running mpirun -np X lmp < in.file ,
it seems
that whatever X is, almost all the 8 cores are fully used. When running only
lmp < in.file without mpirun, CPU usage is around 12.5% which is normal.

Any suggestions about this problem?

it most likely is not a lammps problem.
the problem is either how you use/compiled
MPI, or how you determine CPU utilization
or what the exact input is.

i have never seen anything like that,
and it doesn't make much sense.

for that you have to provide more evidence
and an example of what exactly you are
doing. are you running any of the standard
lammps input, e.g. one from them bench directory?

axel.

3

Thanks axel. I tried to run the input from bench directory,
and CPU utilization is consistent with mpirun -np.
Then I’ve got to look at my input file.
Thank again.

Fan Du