Hi,

It sounds like Open MPI is hitting your system's open file descriptor limit.  If that's the case, one potential workaround is to have your system administrator raise file descriptor limits.

On a compute node, what does "ulimit -a" show (using bash)?

Hope that helps,

--
Samuel K. Gutierrez
Los Alamos National Laboratory 

On Mar 30, 2011, at 5:22 PM, Timothy Stitt wrote:

Dear OpenMPI developers,

One of our users was running a benchmark on a 1032 core simulation. He had a successful run at 900 cores but when he stepped up to 1032 cores the job just stalled and his logs contained many occurrences of the following line:

[d6copt368.crc.nd.edu][[25621,1],0][btl_tcp_component.c:885:mca_btl_tcp_component_accept_handler] accept() failed: Too many open files (24)

The simulation has a single master task that communicates with all the other tasks to write out some I/O via the master. We are assuming the message is related to this bottleneck. Is there a 1024 limit on the number of open files/connections for instance?

Can anyone confirm the meaning of this error and secondly provide a resolution that hopefully doesn't involve a code rewrite.

Thanks in advance,

Tim.

Tim Stitt PhD (User Support Manager).
Center for Research Computing | University of Notre Dame |
P.O. Box 539, Notre Dame, IN 46556 | Phone:  574-631-5287 | Email: tstitt@nd.edu 

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