[cam-users] virtual memory

[Peter Paul Smolka]

On Wed, 19 Nov 2003, Alexander Sen Gupta wrote:

> Date: Wed, 19 Nov 2003 16:28:17 +1100 (EST)
> From: Alexander Sen Gupta <alexg@maths.unsw.edu.au>
> To: cam-users@ucar.edu
> Subject: [cam-users] virtual memory
>
> Hi,
> Im a new CCM user in need of some help. Im trying to compile the coupled
> model on an alpha server. After some minor tweaking compilation proceeds
> through the various components (in a few 10s of seconds), but on reaching
> the ocean component, the virtual memory requirement starts creeping up.
> After about an hour the compliation crashes with the message:
> Fatal:  Virtual address space exceeded.
> gmake: *** [initial.o] Error 1

Dear Alexander,

With ccm3.6 a similar phenomenon could be observed when compiling
for improved optimization all files into one file so cross procedure
optimization can take place.

In this case the solution was:

Separating parts of code out e.g.:

Not the one extreme, compiling each program separately and then
linking but also not the other compiling all into one large object
file.

Potentially you generated this effect indirectly.

Checking your explicite and implicite compiler options as well
as scaling back optimization one or two steps for that part might be
useful. One of the Alpha compilers I know has these effects.

By the way:

A question:

Do you or anybody else have ESMC in Fortran? E.g. not
only the ESMF part linked to *.C programs but the *.C programs
themselves?

If yes I ll save the recoding.

The same applies in principle to netCDF. I am quite sure it does
not exist in Fortran but sometimes luck exists.
>
> The virtual memory requirement is in excess of 2GB!
> Is this memory requirement normal? If not, any ideas what might be causing
> the build up?
>
> Thanks for any help.
> Alex
>

Best regards, Peter



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Dr. Peter P. Smolka
University Muenster
Geological Institute
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D-48149 Muenster

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