Timing StatisticsΒΆ

The amrclaw and geoclaw Fortran codes provide some timing information at the end of a run (and also stored at the end of the file fort.amr in the output directory).

Typical output looks like this:

============================== Timing Data ==============================

Integration Time (stepgrid + BC + overhead)
Level           Wall Time (seconds)    CPU Time (seconds)   Total Cell Updates
  1                     2.850                  2.853            0.288E+07
  2                    13.214                 41.552            0.373E+08
  3                    92.774                370.259            0.260E+09
total                 108.838                414.664            0.301E+09

All levels:
stepgrid              101.440                392.473
BC/ghost cells          5.014                 19.801
Regridding             40.508                 40.447
Output (valout)        15.413                 15.402

Total time:           165.483                472.470
Using  4 thread(s)

Note: The CPU times are summed over all threads.
      Total time includes more than the subroutines listed above


This was generated by running the code in $CLAW/amrclaw/examples/advection_3d_swirl with a third level of AMR added (and additional refinement factor 2) so that more grids are generated.

Note the following:

  • All times are in seconds.
  • For this example, more than 85% of the integration time is spent on the finest Level 3 grids.
  • OpenMP was used in this run, specifying OMP_NUM_THREADS=4. Grid patches are then split up between threads (see Using OpenMP). This test problem has enough grid patches that the time spent in stepgrid (where updating each patch using the finite volume method) uses roughly 1/4 as much wall time as CPU time, and similarly for filling ghost cells.
  • Regridding and output are done in serial mode, however, so the wall time for these portions agree with the CPU time.