Score:0

Not enough slots available in the system with OpenMPI

za flag

I am launching a code using openmpi, that I have compiled simply doing

mpif90 bin.f90 -llapack -lblas -o bin.x

If I do

mpirun -np 4 bin.x

I get

"There are not enough slots available in the system to satisfy the 4 slots that were requested by the application."

However, I have 4 cpus, since doing

cat /proc/cpuinfo | grep processor | wc -l

I get 4.

This is happening since I have updated the system and passed to 20.04.2

Could someone explain what is happening, please?

hr flag
Are you sure you have 4 cpus (or cores) rather than 4 hyperthreads? See for example [Unable to use all cores with mpirun](https://stackoverflow.com/questions/48835603/unable-to-use-all-cores-with-mpirun)
Gippo avatar
za flag
Apparently, using lstopo I find two cores, each one with two PU (Processor Unit?) This means that I have only 2 cpus, then? I am wondering why this is the first time that I get this when I run mpirun -np 4 .
hr flag
I don't know - perhaps it was configured before with `--use-hwthread-cpus` as the default?
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