[ptp-dev] Questions about PTP SDM debugger

[Dave Wootton <dwootton@xxxxxxxxxx>]

I have a first attempt at changes to
my PE proxy to allow a PE application to be debugged using the SDM debugger,
and have some questions
1) Around line 188 of SDMDebugger.java,
I see code that sets up the --numnodes parameter to sdm with number of
processes + 1. Right now, my code isn't setting up the right job attributes
to satisfy JobAttributes.getNumberOfProcessesAttributeDefinition
so I was getting a null pointer exception. I temporarily hard coded --numnodes
as 2 to get around that.. 
Is there an assumption that there is
only one application task per node when debugging or is this really number
of application tasks + 1 and number of tasks per node doesn't matter?
For PE, the user can run as many tasks
per node as he likes as long as system resources are available. If the
user specifies a hostlist, I could probably figure out the number of nodes
used by the application by looking at the hostlist before starting the
debugger. If the user is using LoadLeveler to allocate nodes, then I have
no idea how many nodes, or even what nodes the application will run on
since LoadLeveler doesn't get control to handle node allocation until sometime
after the job is submitted.
2) I think I have the argument list
to sdm set up properly, where argv[0] is the sdm executable name (sdm),
the next elements of argv are whatever are passed as debugArgs, then the
pathname of the application executable and finally a NULL (to satisfy execve)
When I try to invoke the debugger, I
see the sdm process show up for a few seconds then it exits. If I'm quick
enough, I can attatch to sdm with gdb then let it run to completion. It
looks like sdm is just running for a few seconds then exits with an exit(1)
call somewhere in main.
Is there any way I can turn on some
debug output to see what is going wrong with SDM?
3) I am intercepting stdout and stderr
for teh sdm process so that they can either be sent to a console or redirected
to a file. In either case, I'm not seeing anything from SDM. If I try to
redirect stdio for sdm, will that cause problems?
Dave