Re: Petsc Error

[Berend van Wachem <berend@xxxxxxxxxxx>]

Hi Barry,

Yes, your hint seems correct; a single process can "only" allocate 3 
gigabytes of memory, even if there is more physical memory present.

Is the only work around to run parallel?

Thanks,
Berend.


Barry Smith wrote:
>   On most OS's just because you have greater than a certain amount of
> physical memory does not mean that a SINGLE process can utilize it.
> For example, many times a single process is limited to 2, 3 or 4 gigabytes.
> This is EVEN with 64 bit pointers (and certainly with 32 bit).
>
>    Barry
>
> Run a simple C program that mallocs a chunk of memory. How much you 
> you malloc?
>
> On Tue, 9 Oct 2007, Berend van Wachem wrote:
>
> > Hi,
> >
> > I ran the same command again, running top, and got the result
> >
> > Mem:   6220940k total,  5879056k used,   341884k free,   143992k buffers
> > Swap:  1951888k total,     2584k used,  1949304k free,  2363516k cached
> >
> >   PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
> > 19117 berend    25   0 3037m 2.5g 3508 R  100 41.4   0:44.96 MultiFlow
> >
> >
> >
> > just before it crashed. I have a 2 processor machine with total 6 GB of memory
> > (2 times 3 gb?), so I don't think it should be out of memory. How can I verify
> > this for sure?
> >
> > Thanks,
> >
> > Berend.
> >
> >
> >
> > Matthew Knepley wrote:
> > > On 10/9/07, Berend van Wachem <berend@xxxxxxxxxxx> wrote:
> > > > Hi,
> > > >
> > > > On the command
> > > >
> > > >   ierr = DACreateLocalVector(da,g); CHKERRQ(ierr);
> > > >
> > > > I get the error
> > > >
> > > >
> > > > [0]PETSC ERROR: PetscMallocAlign() line 61 in src/sys/memory/mal.c
> > > > Memory requested 6050600
> > > > [0]PETSC ERROR: PETSC: Attaching gdb to Debug/MultiFlow of pid 19087 on
> > > > display :0.0 on machine tfdpc102
> > > >
> > > >
> > > > What does it mean exactly? Out of memory?
> > > Yes. This is strange. The line above these two should read "Out of memory".
> > >
> > >   Matt
> > >
> > > > Thanks,
> > > > Berend.