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mpiexec is ignoring the no. of processes after each hostname in the hostfile

YaDev
Beginner
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Running MPI using a hostfile like this 

mpiexec -f hostfile executable

The hostfile has the content, for example

host1:4

host2:2

but MPI just runs the maximum number of processes on each host. It just completely ignore the process numbers in the hostfile??

 

 

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TobiasK
Moderator
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@YaDev 
You are using the hostfile option while you need the machine file option. A hostfile does not contain the number of slots available, only the machinefile contains this information.

https://www.intel.com/content/www/us/en/developer/articles/technical/controlling-process-placement-with-the-intel-mpi-library.html

mpirun -machinefile hostfile executable
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YaDev
Beginner
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Oh ok thank you!

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YaDev
Beginner
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Hello again,

Would Intel not consider instead of having this -machinefile flag, just merge it into the hostfile under the -f flag just like what MPICH is doing? There is no reason to have this separate -machinefile flag, right?

 

With just the -f hostfile to list

Example 1)

host1

host2

host3

...

 

Example 2)

host1:3

host2

host3:5

...

 

The -machinefile is just quite redundant IMHO. 

 

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