Open MPI logo

Open MPI User's Mailing List Archives

  |   Home   |   Support   |   FAQ   |  

This web mail archive is frozen.

This page is part of a frozen web archive of this mailing list.

You can still navigate around this archive, but know that no new mails have been added to it since July of 2016.

Click here to be taken to the new web archives of this list; it includes all the mails that are in this frozen archive plus all new mails that have been sent to the list since it was migrated to the new archives.

Subject: [OMPI users] mpi job is blocked
From: Richard (codemonkee_at_[hidden])
Date: 2012-09-25 02:20:58

I have 3 computers with the same Linux system. I have setup the mpi cluster based on ssh connection.
I have tested a very simple mpi program, it works on the cluster.

To make my story clear, I name the three computer as A, B and C.

1) If I run the job with 2 processes on A and B, it works.
2) if I run the job with 3 processes on A, B and C, it is blocked.
3) if I run the job with 2 processes on A and C, it works.
4) If I run the job with all the 3 processes on A, it works.

Using gdb I found the line at which it is blocked, it is here

#7 0x00002ad8a283043e in PMPI_Allreduce (sendbuf=0x7fff09c7c578, recvbuf=0x7fff09c7c570, count=1, datatype=0x627180, op=0x627780, comm=0x627380)
    at pallreduce.c:105
105 err = comm->c_coll.coll_allreduce(sendbuf, recvbuf, count,

It seems that there is a communication problem between some computers. But the above series of test cannot tell me what
exactly it is. Can anyone help me? thanks.