poll: protocol failure during circuit creation


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You may see this message if you attempt to run too many MPI programs in a short period of time. For example, in Linux and when using the ch_p4 device (without the secure server or ssh), mpich uses rsh to start the MPI processes. Depending on the particular Linux distribution and verison, there may be a limit of as few as 40 processes per minute. When running the mpich test suite or starting short parallel jobs from a script, it is possible to exceed this limit.
To fix this, you can do one of the following:

    1. Wait a few seconds between running parallel jobs. You may need to wait up to a minute.


    2. Modify /etc/inetd.conf to allow more processes per minute for rsh. For example, change 

    shell stream tcp nowait root /etc/tcpd2 in.rshd
    to 
    shell stream tcp nowait.200 root /etc/tcpd2 in.rshd


    3. Use the ch_p4mpd device or the secure server option of the ch_p4 device instead. Neither of these relies on inetd.


Up: Frequently Asked Questions Next: Using SSH Previous: Notes on getting MPICH running Under Linux