On Mar 5, 2009, at 9:29 AM, Shanyuan Gao wrote:
I am doing some research on MPI barrier operations. And I am ready to do some performance test. I wonder if there are any applications that using barriers a lot. Please let me know if there is any. Any comments are welcomed. Thanks!
I don't remember who originally said it, but I've repeated the statement: any MPI program that relies on a barrier for correctness is an incorrect MPI application.
There's anecdotal evidence that throwing in a barrier every once in a while can help reduce unexpected messages (and other things), and therefore improve performance a bit. But that's very application dependent, and usually not frequent.
Why do you want to do a barrier? Particularly one that sounds like it might be in your critical performance path?
-- Jeff Squyres Cisco Systems
