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Subject: Re: [OMPI users] OpenMPI 1.2.5 race condition / core dump with MPI_Reduce and MPI_Gather
From: Christian Bell (christian.bell_at_[hidden])
Date: 2008-02-28 14:55:08

On Thu, 28 Feb 2008, Gleb Natapov wrote:

> The trick is to call progress only from functions that are called
> directly by a user process. Never call progress from a callback functions.
> The main offenders of this rule are calls to OMPI_FREE_LIST_WAIT(). They
> should be changed to OMPI_FREE_LIST_GET() and dial with NULL return value.

Right -- and it should be easy to find more offenders by having an
assert statement soak in the builds for a while (or by default in
debug mode).

Was if it was ever part of the (or a) design to allow re-entrant
calls to progress from the same calling thread ? It can be done but
callers have to have a holistic view of how other components require
and make the progress happen -- this isn't compatible with the Open
MPI model of independent dynamically loadable components.

(QLogic Host Solutions Group, formerly Pathscale)