topic mpiexec -hosts differences in MPICH and Intel MPI in Intel® MPI Library

mpiexec -hosts differences in MPICH and Intel MPI

zelenko__yauheni — Fri, 11 Jan 2019 19:35:29 GMT

What is differences in handling mpiexec -hosts in MPICH and Intel MPI? It seems that Inte MPI doesn't recognize <host>:<number processes> syntax.

Hi,

Dmitry_G_Intel — Thu, 24 Jan 2019 13:14:00 GMT

Hi,

Could you please provide full command line and version of Intel MPI?

I tried MPICH 2 1.5 and MPICH

zelenko__yauheni — Thu, 24 Jan 2019 20:01:56 GMT

I tried MPICH 2 1.5 and MPICH 3.3 and Intel MPI 2018.4.

Command line was simple: mpiexec -host "host1:2,host2:2" <cpi> example.

MPICH mpiexec (Hydra) launched 4 processes. Intel MPI mpiexec launched number of CPUs on both hosts processes.

This is the expected behavior

James_T_Intel — Wed, 30 Jan 2019 13:48:59 GMT

This is the expected behavior. Intel® MPI Library does not support this syntax for the -hosts option. There was no specification for the number of ranks in a recognized manner, therefore the default is to put a number of ranks equal to the number of cores. In order to achieve your desired behavior, please use the -machinefile <file> option. The specified file should contain the <host>:<ranks> syntax, with one host per line.

But if Intel MPI mpiexec is

zelenko__yauheni — Wed, 30 Jan 2019 18:40:45 GMT

But if Intel MPI mpiexec is based on MPICH Hydra why Hydra's -host syntax could not be supported? I don't think that creating temporary files for -machinefile is better solution then more flexible -hosts.