[mpich-discuss] mpd_uncaught_except_tb and stdin problem

[Thomas Ruedas]

Hi,
I am running a parallel code using MPICH2-1.2 on different sorts of 
machines and keep seeing a strange error message or warning related to 
STDIN handling when starting a run. For instance, when running it on an 
8-CPU Mac Pro (with Intel Fortran 11.1) in the foreground (i.e., taking 
the prompt and writing to stdout), it runs just fine. When I start the 
very same job as a background job e.g. with
mpiexec -machinefile machines -n 4 stagyympi >& scr.out &
it starts up ok, does the initial stuff apparently correctly, and then 
crashes with this error (hostname changed for security reasons):
mpiexec_my.machine.my.domain: mpd_uncaught_except_tb handling:
   <type 'exceptions.IOError'>: [Errno 9] Bad file descriptor
     /Users/ruedas/local/bin/mpiexec  1087  handle_stdin_input
         sys.stdin.flush()  # probably does nothing
     /Users/ruedas/local/bin/mpdlib.py  780  handle_active_streams
         handler(stream,*args)
     /Users/ruedas/local/bin/mpiexec  530  mpiexec
         rv = streamHandler.handle_active_streams(timeout=1.0)
     /Users/ruedas/local/bin/mpiexec  1446  <module>
         mpiexec()

I also run the code on a Linux cluster (with Intel Fortran 9.1 and the 
same MPICH2 version), where I always start it as a background job as 
shown above. There it runs ok, although I do get this warning:

mpiexec_my.cluster.my.domain (handle_stdin_input 1089): stdin problem; 
if pgm is run in background, redirect from /dev/null
mpiexec_my.cluster.my.domain (handle_stdin_input 1090):     e.g.: 
mpiexec -n 4 a.out < /dev/null &

repeatedly. It doesn't seem to do anything bad, it's just there, and I 
don't know why.
I should point out that the program reads input only from a file, but 
not from the prompt or interactively from stdin.
Can someone please explain to me what this stdin stuff is about and why 
these messages appear and tell me what to do to run the program in the 
background on the Mac? I had the impression that the installation went 
ok on both machines.
Thanks,
Thomas
-- 
-----------------------------------
Thomas Ruedas
Department of Terrestrial Magnetism
Carnegie Institution of Washington
http://www.dtm.ciw.edu/users/ruedas/