I grabbed the new OMPI 1.6.1 and ran my test that would cause a hang with 1.6.0 
with low registered memory.  From reading the release notes rather than hang I 
would expect:

* lower performance/fall back to send/receive.
* a notice of failed to allocate registered memory

In my case I still get a hang, is this expected?  This is running with default 
registered memory limits and I do appreciate  the message that I only have 4GB 
of registered memory of my 48.  We will also be fixing our load to raise this 
value, which should make this issue moot.

Honestly I think what I would want is for MPI to blow up saying "can't allocate 
registered memory, fatal, contact your admin", rather than fall back to 
send/receive and just be slower.

Am I reading the release notes correctly?  Is there a tunable setting to blow 
up rather than fallback?

Brock Palen
www.umich.edu/~brockp
CAEN Advanced Computing
bro...@umich.edu
(734)936-1985




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