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Subject: Re: [OMPI users] Infiniband performance Problem and stalling
From: Paul Kapinos (kapinos_at_[hidden])
Date: 2012-08-28 04:13:21

after reading this:

On 08/28/12 04:26, Randolph Pullen wrote:
> - On occasions it seems to stall indefinately, waiting on a single receive.

... I would make a blind guess: are you aware about IB card parameters for
registered memory?

"Waiting forever" for a single operation is one of symptoms of the problem
especially in 1.5.3.


P.S. the lower performance with 'big' chinks is known phenomenon, cf.
(image on bottom of the page). But the chunk size of 64k is fairly small

Dipl.-Inform. Paul Kapinos   -   High Performance Computing,
RWTH Aachen University, Center for Computing and Communication
Seffenter Weg 23,  D 52074  Aachen (Germany)
Tel: +49 241/80-24915