HI Jeff, Ralph,
Yes, I call MPI_COMM_SPAWN in multiple threads simultaneously.
Because I need to expose my parallel algorithm as a web service, I need
multiple clients connect and execute my logic as same time(ie mutiple
threads).
For each client , a new thread is created (by Web service framework) and
inside the thread,MPI_Init_Thread() is called if the MPI hasnt been
initialized.
The the thread calls MPI_COMM__SPAWN and create new processes.
So ,if this is the case isn't there any workarounds ?
Thanks in advance,
umanga
Jeff Squyres wrote:
On Sep 16, 2009, at 9:53 PM, Ralph Castain wrote:
Only the obvious, and not very helpful one: comm_spawn isn't thread
safe at this time. You'll need to serialize your requests to that
function.
This is likely the cause of your issues if you are calling
MPI_COMM_SPAWN in multiple threads simultaneously. Can you verify?
If not, we'll need to dig a little deeper to figure out what's going
on. But Ralph is right -- read up on the THREAD_MULTIPLE constraints
(check the OMPI README file) to see if that's what's biting you.
