[MPICH] MPICH2 use of shared memory

[David Ashton]

James,

The MPICH2 ssm channel allocates shared memory on demand when processes on
the same node first communicate with each other.  A fixed amount of shared
memory is allocated for each queue.  If you have too many queues on a single
node you will eventually run out of shared memory as determined by the
system but MPICH2 does not impose any maximum.

-David Ashton

-----Original Message-----
From: owner-mpich-discuss at mcs.anl.gov
[mailto:owner-mpich-discuss at mcs.anl.gov] On Behalf Of James S Perrin
Sent: Wednesday, June 15, 2005 9:57 AM
To: mpich-discuss at mcs.anl.gov
Subject: [MPICH] MPICH2 use of shared memory

Hi,
	Under MPICH 1 the p4 device required the P4_GLOBMEMSIZE setting to
the amount 
of shared memory available. Is there an equivalent or need of one when using

MPICH2's ch3:ssm device?

Regards
James
-- 
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James S. Perrin,                   | email: james.perrin at manchester.ac.uk
Manchester Visualization Centre,   | www.sve.man.ac.uk/General/Staff/perrin
Kilburn Building, The University,  | tel: +44 161 275 6945
Manchester, England. M13 9PL.      | fax: +44 161 275 6800/6040
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"The test of intellect is the refusal to belabour the obvious" -Alfred
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