memory reporting question

[Matt Funk]

Ok,

i am more confused now.
The following is part of my code:

  PetscLogDouble mem;
  PetscMemoryGetCurrentUsage(&mem);
  cout<<"PetscMemoryGetCurrentUsage: "<<mem<<"\n"; cout.flush();
  PetscMemoryGetMaximumUsage(&mem);
  cout<<"PetscMemoryGetMaximumUsage: "<<mem<<"\n"; cout.flush();


This is what is reported:

PetscMemoryGetCurrentUsage: 5.25525e+08
PetscMemoryGetMaximumUsage: 3.09055e+08


Now, unless i am missing something obvious, i am completely confused how it is 
that the maximum usage can be less than the current usage.

What am i missing here?


thanks
matt




On Thursday 17 September 2009, you wrote:
> On Thu, Sep 17, 2009 at 6:04 PM, Matt Funk <mafunk at nmsu.edu> wrote:
> > Hi,
> >
> >
> > I am wondering whether the -memory_info option and the
> > PetscMemoryGetMaximumUsage<http://www.mcs.anl.gov/petsc/petsc-as/snapshot
> >s/petsc-current/docs/manualpages/Sys/PetscMemoryGetMaximumUsage.html#Petsc
> >MemoryGetMaximumUsage>() call report different things.
> >
> >
> > The reason i am asking is because i call the PetscMemoryGetCurrentUsage
> > fcn in my code and it shows:
> > 5.25558e+08.
>
> This call get_rusage(), so it gives you the entire process size.
>
> > At the end of the run the -memory_info option reports:
> > max process malloc()'ed: 4.00524e+08
>
> This is a sampling of rusage every time an object is destroyed.
>
> > max petsc malloc()'ed: 1.15254e+08.
>
> This is all the memory malloced using PetscMalloc() summed.
>
>   Matt
>
> > So i am a little confused by those numbers unless the fcn call is the
> > more complete picture (as said on the manual page)
> >
> >
> > I guess then my question is whether the -memory_info corresponds to the
> > PetscMalloc* fcns?
> >
> >
> > thanks
> > matt


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