CODEWITHSUNDEEP
multicorempinodes
Mibou
Mibou

Reputation: 976

MPI has only master nodes

I'm trying to use MPI with my 4 cores processor. I have followed this tutorial : http://debianclusters.org/index.php/MPICH:_Starting_a_Global_MPD_Ring

But at the end, when I try the hello.out script, I get only server process (master nodes) :

mpiexec -np 4 ./hello.out
Hello MPI from the server process!
Hello MPI from the server process!
Hello MPI from the server process!
Hello MPI from the server process!

I have searched all around the web but couldn't find any clues for this problem.

Here is my mpdtrace result : 

[nls@debian] ~ $ mpd --ncpus=4 --daemon
[nls@debian] ~ $ mpdtrace -l
debian_52063 (127.0.0.1)

Shouldn't I get one trace line per core ?

Thanks for your help,

Malchance

Upvotes: 2

Views: 670

Answers (1)

Jonathan Dursi
Jonathan Dursi

Reputation: 50947

95% of the time, when you see this problem -- MPI tasks not getting the "right" rank ids, usually ending up all being rank zero -- it means there's a mismatch in MPI libraries. Either the mpiexec is doing the launching isn't the same as the mpicc (or whatever) used to compile the program, or the MPI libraries the child processes are picking up on launch (if linked dynamically) are different than those intended. So I'd start by double checking those things.

Upvotes: 2

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