Hi Bogdan!
It seems your advice alleviated 'insufficient virtual memory' problem,
so exec-shield was in fact the stumbling stone.
echo 0 > /proc/sys/kernel/exec-shield
was all it took. I will now find out how to do the same thing at boot
time. Either by adding options in grub.conf or do the setting
in /etc/sysctl.conf
best regards, Jess Michelsen
On Thu, 2005-01-13 at 14:54 +0100, Bogdan Costescu wrote:
> On Thu, 13 Jan 2005, Jess Andreas Michelsen wrote:
>
> > forrtl: severe (41): insufficient virtual memory
> >
> > originating from one or more of the nodes. The crash always happens at
> > the same place in the program, but the nodes on which it happens differ
> > between runs.
>
> I have seen some strange behaviour as well with Fortran codes due to
> the exec-shield feature of the recent Red Hat kernels and maybe some
> other (NPTL ?) related changes. They happen as well when using a
> non-parallel binary (so LAM has nothing to do with it) and the way I
> got rid of them was to disable exec-shield (there's a /proc entry that
> can be changed) and to increase the defaut stack size. I've done this
> mainly on FC1/RHEL3 on lots of machines, but also tried a few runs on
> a FC3 machine.
>
> > A mere 'top' shows the memory usage being stable, i.e. not growing over
> > time, and appr. 1/10 of the physical memory on each node is reported as
> > utilized.
>
> This would indeed support my thoughts above: there is enough memory,
> but the application doesn't get it the way it expects.
>
|
