[Beowulf] [owner-chemistry at ccl.net: CCL:G: parallel G03 in Linux cluster]

Mark Hahn hahn at physics.mcmaster.ca
Sat Mar 18 09:22:34 PST 2006

> >> The OpenMP parallelization should also work without Linda - but of course
> >> limited to some routines and 2 cores.

I wonder if this is only true if you, for instance, compile gaussian
with a PGI demo license or something.  also, the normal (old) way of 
using SMP is fork-based parallelism with SYSV shm.  is this separate
(orthogonal) to OpenMP-based parallelism?  I suspect the latter is only
used for SMP parallelism within parallelized blas libraries like MKL.

> machines with single dual-core CPUs. Let's rephrase: ...but limited to the
> cores in each of the machines.

mosix, I believe, provides network-shared SYSV shm.  I wonder if anyone has 
tried to use gaussian that way.  depending on the sharing patters, it might 
work pretty well - my understanding is that the shm is used mainly for
caching intermediate values (integrals?), which might be
write-once-read-mostly, and therefore friendly to the kind of caching 
necessary for any page-based net-shm implementation.

regards, mark hahn.

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