[mpich-discuss] Hydra & process clean up

[Jain, Rohit]

Haven't seen any response (not sure it was received). Resending mail.

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I am using mpich2-1.4.1 linux version. Since I moved to hydra (from mpd), I am often seeing orphaned processes, when ctlr-c is done.

This is my call sequence:
main_exec -> mpiexec -> proc1 -> subp1
                     -> proc2 -> subp2

When I do ctrl-c, I "don't" see this message 'Ctrl-C caught... cleaning up processes', and often one of the subp* is left around.


I tried doing this call sequence too:
mpiexec -> proc1 -> subp1
         > proc2 -> subp2

I "do" see message 'Ctrl-C caught... cleaning up processes', but one of the subp is still left around.


I can also call my executable in single core mode:
proc -> subp

With ctrl-c, it does trap SIGINT, and pass it down to subp. But, with mpiexec involved, I don't see 'proc' or 'subp' trapping any signal.

Questions:
1- What mpiexec is really doing when it says 'cleaning up processes'?
2- What signal should be trapped in proc (child processes) for ctrl-c, while running through mpiexec? Is there a way to dump signal tracing in MPI code?
3- Is mpiexec supposed to terminate whole process tree, including sub-processes?
4- mpd used to cleanup whole process tree. Is this intentional change in hydra?

Regards,
Rohit


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