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Subject: [OMPI users] OMPI 1.4: connectivity_c fails, ring_c and hello_c work
From: Matthew MacManes (macmanes_at_[hidden])
Date: 2009-12-09 18:54:32

What is the difference between connectivity_c and ring_c or hello_c? Under
what circumstances should one fail and not the others...

I am having a huge problem with openMPI, and trying to get to the bottom of
it by understanding the differences between the example files, connectivity,
hello, and ring.

1st off, ring_c and hello_c seem to work fine with up to -np 250

connectivity_c works reliably when -np <5, but less that 30% of the time
when -np >6. When it does not work, it just hangs.. no output.. here is a
screenshot of TOP with mpirun -np 8 connectivity_c hanging..

Under what circumstances should this happen?

I am using Ubuntu 9.10, kernel 2.6.31-16, Nehelem processors.
Hyperthreading is enabled.

Matthew MacManes
PhD Candidate
University of California- Berkeley
Museum of Vertebrate Zoology
Phone: 510-495-5833
Lab Website:
Personal Website: