[ptp-user] PTP debug limitation

[Todd Eavis <eavis@xxxxxxxxxxxxxxx>]

Hi,

I'm not sure if this is a bug or a configuration problem (and I haven't 
seen a similar listing in the archives).

I have set up a new PTP environment for my graduate students that is 
being used to develop and debug on a remote Linux cluster (a frontend 
node and 16 backend compute nodes). The cluster sits behind a login 
server so SSH tunneling is being used for all connections. For the most 
part, everything is working. Projects can be created, built and run. The 
problem is with the PTP Debug perspective. I am able to debug 
applications properly, but only up to a limit of 5 processes (I am using 
one per node). Any attempt to use a larger process count causes the 
session to hang and then timeout after the "initialising debug processes 
(6)" box appears. PTP generates an error box saying "Error: start 
debugger request error". Eclipse provides the following error:

Error
Thu Oct 22 09:35:39 EDT 2009
Time out for this request.

org.eclipse.core.runtime.CoreException: Time out for this request.
  at 
org.eclipse.ptp.debug.internal.core.PSession.connectToDebugger(PSession.java:153) 

  at 
org.eclipse.ptp.launch.ParallelLaunchConfigurationDelegate$1$1.run(ParallelLaunchConfigurationDelegate.java:191) 

  at 
org.eclipse.jface.operation.ModalContext$ModalContextThread.run(ModalContext.java:121) 


There are three additional points to note. First, "running" the larger 
process counts is not a problem. I can run 17 processes either from the 
command line or from the PTP runtime perspective, using essentially the 
same run/debug configuration. Second, there does not appear to be any 
problem with the backend nodes themselves. In other words, I can modify 
the mpi_hosts files to include any group of 5 nodes (eg, frontend and 
nodes 1-4, frontend and nodes 6-9). This works just fine. I just can't 
add a 6th process to the debug configuration. Third, I have set up both 
PTP 2.1 and PTP 3.0. The result is the same in both versions.

Any ideas?

Cheers,

Todd

--
___________________________________

Todd Eavis, PhD
Associate Professor
Concordia Research Chair, Tier II
Department of Computer Science
Concordia University, Montreal
email: eavis@xxxxxxxxxxxxxxx
web: http://www.cs.concordia.ca/~eavis
___________________________________