Performance Log Question

Barry Smith bsmith at mcs.anl.gov
Thu Jul 31 22:43:48 CDT 2008


   Code is not using PETSc to do anything. Therefore there isn't going  
to be much in the way
of logging. PETSc's logging only logs our own code. It doesn't  
magically log all flops in
the code.

    Barry

On Jul 31, 2008, at 10:40 PM, Waad Subber wrote:

> Thank you Barry for the reply. Yes I get more or less the same log  
> when I run with the option -log_summary. Please have a look at the  
> attached file.
>
> Thanks
>
> Waad
>
> --- On Thu, 7/31/08, Barry Smith <bsmith at mcs.anl.gov> wrote:
> From: Barry Smith <bsmith at mcs.anl.gov>
> Subject: Re: Performance Log Question
> To: petsc-users at mcs.anl.gov
> Date: Thursday, July 31, 2008, 9:27 PM
>
>    From the file, it seems you never make an nontrivial PETSc calls.
> Do you get the same
> log if you just run with -log_summary?
>
>     Barry
>
>
>
> Event                Count      Time (sec)     Flops/
> sec                         --- Global ---  --- Stage ---   Total
>                     Max Ratio  Max     Ratio   Max  Ratio  Mess   Avg
> len Reduct  %T %F %M %L %R  %T %F %M %L %R Mflop/s
> ------------------------------------------------------------------------------------------------------------------------
>
> --- Event Stage
>  0: Main Stage
>
> ------------------------------------------------------------------------------------------------------------------------
>
>
>
> On Jul 31, 2008, at 4:33 PM, Waad Subber wrote:
>
> > Hello,
> >
> > I am currently solving a 1.2 million by 1.2 million linear system
> > using PETSc 2.3.3, Patch 13 using domain decomposition (iterative
> > substructuring using a Krylov Subspace Solver). I'm using a 120 CPU
> > cluster with InfiniBand interconnect; each node has 8 cores -- 2
> > quad-core Xeon CPUs (X5365) at 3.0 GHz, each node having 32 GB of  
> RAM.
> >
> > After running my code, I generate a log using the following:
> >        CALL
> PetscLogPrintSummary(PETSC_COMM_WORLD,"log.txt",ierr)
> >
> > When looking at the log output, I noticed that the peak and average
> > number of Flops seems fairly low -- in the case of one run, a peak
> > of 6.0e7 flops with an
>  average value of 5.2e7. The exact log output
> > is:
> >
> >                          Max       Max/Min        Avg      Total
> > Time (sec):           5.283e+01      1.02357   5.169e+01
> > Objects:              2.600e+02      1.00000   2.600e+02
> > Flops:                3.187e+09      1.69853   2.721e+09  3.265e+11
> > Flops/sec:            6.165e+07      1.69865   5.264e+07  6.317e+09
> > Memory:               6.081e+07      1.39801              6.608e+09
> > MPI Messages:         1.067e+05      1.00000   1.067e+05  1.281e+07
> > MPI Message Lengths:  5.205e+08      1.00081   4.875e+03  6.245e+10
> > MPI Reductions:       1.898e+01      1.00000
> >
> > Is my interpretation correct about this being a fairly low flop
> > count? Does this mean there's an issue with my code?
> >
> > I am attaching my log file
> >
> > Thanks
> >
> > Waad
> >
> >
> >
>  <log.txt>
>
>




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