Re: ccm3 using both SMP and MPI


Subject: Re: ccm3 using both SMP and MPI
From: Jim Rosinski (rosinski@cgd.ucar.edu)
Date: Mon Oct 29 2001 - 12:12:19 MST


On Mon, 29 Oct 2001, Norm Wood wrote:

> I'm interested in finding out if anyone has had success running
> ccm3.10.11.brnchT.366physics.4 on dual-processor linux boxes using
> Portland Group's PGF90 compiler.

The symptoms you describe sound like the slave stacksize isn't big enough.
The example rundeck provided with the distribution (run.pc.linux.csh) should
set this number to a value adequate for the default model (look for setenv
MPSTKZ 40M). To test if this is the problem, I'd try running at very low
resolution (e.g. T5) and see if it works with threading turned on (-mp arg to
pgf90). If you're adding constituents, history variables, or running at a
higher resolution the 40M may not be big enough.

I wish these blasted systems would just default magic numbers like MPSTKZ to
"as big as possible", but none of them do.

If the above suggestions fail, try running in SPMD mode. This allows the
code to use multiple processors, and doesn't require the -mp option.

Regards,

Jim Rosinski
CCM Core Group



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