[MPICH] Deadlock with multiple threads

[Rusty Lusk]

Can you post the code?  It sounds like a good test program.

From: "David Minor" <david-m at orbotech.com>
Subject: [MPICH] Deadlock with multiple threads
Date: Thu, 8 Dec 2005 17:02:56 +0200

> Hi Mpiers,
> 
> The following situtation leads me to deadlock, why?
> 
> I have three nodes and two threads on each node. 
> There are two communicators, on each node thread 1 (t1) is using communicator 1 (c1)
> and thread 2 is using communicator 2.
> 
> c1 is involved in a bcast on all three nodes on t1
> c2 on all t2's is in a recv from any source, for which a send has not yet been issued.
> 
> Why does the bcast on c1 deadlock?  This seems to violate one of the rules for multi-threaded MPI.
> 
> When I run the above scenario on 2 nodes there is no deadlock.
> 
> Regards,
> David