Re: [bgl-discuss] crashes in VN mode

[William Gropp <gropp@xxxxxxxxxxx>]

At 05:01 PM 2/8/2005, Boyana Norris wrote:
> I've been running some (16 and 32-processor) GYRO simulations, built with
> /home/norris/software/bin/mpif90 (rip-off of Satish's version, just
> changed from f77 to f90), and the following optimization options:
>
> -qbgl -qarch=440d -qtune=440
> -qcache=level=1:type=i:size=32:line=32:assoc=64:cost=8
> -qcache=level=1:type=d:size=32:line=32:assoc=64:cost=8
> -qcache=level=2:type=c:size=4096:line=128:assoc=8:cost=40 -qhot=simd -O3
>
> This runs fine in coprocessor mode but crashes (with core dump) in vn mode
> after the initialization of the simulation otherwise.

Another possible source of problems is memory exhaustion - in VN mode, you 
have only half as much memory per MPI process.  I seem to remember that 
running out of memory did not generate "nice" results (i.e., a clean death).

Does anyone know if there are alternate entry points for the C library 
routines?  It would be nice to replace malloc with

void *malloc( size_t s )
{
void *p = _malloc( s );
if (!p) { reliably scream and die; }
return p;
}

Ditto for brk (I'm not sure which Fortran may use).

Bill


> I'm starting to experiment with different compiler options, but wanted to
> ask in the meanwhile if compiling with the intention of running in virtual
> node mode is supposed to be done differently than when running in
> coprocessor mode?
>
> Also, what debugger should I be using and how (in conjunction with
> mpirun)?
>
> Thanks!
> Boyana
>
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William Gropp
http://www.mcs.anl.gov/~gropp 

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