[ptp-dev] Re: Re: About sdm and mpi jobs

[yang ke <jodiusyk@xxxxxxxxx>]

Thanks,Greg. 

 

Still I get a few questions  :-):

     when debug flag is on, we will start a debug job. In orte_server.c , debug_spawn() will allocate two job structures: one for the application, the other for sdm, and then sdms are launched in debug_spawn(am I right?) .

     1. Does orte launch the application at the same time as it launches sdm?

     2. sdm servers internally fork a gdb to launch the program( execlp gdb_path,gdb, -q, -tty, /dev/null, -mi, program,NULL). Is this program a newer one?

     3.  if 2 is, then it seems like gdb debugging a local single program. but the fact is , ptp parallel debugger works  quite well .
     4. Will the new resource manager part in future PTP provides interface for slurm?

 

Thank you.

 

    BTW, My gdb version is 6.0post-0.20031117.6rh. I will consult the administrator for a higher version.

Integration with resource mangers is something we're working on right
now, but is not currently available in PTP. At the moment, you have
to do the allocation request manually before you launch the job
(possibly even before you launch Eclipse if environment variables are
used.)

In any case, the allocation you need to make for debugging an MPI job
with the SDM will depend on your resource management system. The SDM
itself requires an allocation of n+1 processes (where n is the number
of processes in the job being debugged). It will then fork/exec n
copies of gdb (one per process being debugged) and n copies of the
program being debugged. If your resource manager somehow manages the
allocation of forked processes, you may potentially need to request
an allocation of 3n+1 processes to debug the job. The usual way to
deal with this would be to provide a debug or interactive queue that
these types of jobs can be submitted to.

Threading support has been in gdb for a while, but I'm not sure if it
was available before version 6. Also, it depends on threading support
being available on your machine architecture and operating system.
What version of gdb to do you have (gdb -v), and what type of system
is it?

Regards,

Greg

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