Bug #3417

Application CPU time is not correct for OpenMP support

Added by Knödlseder Jürgen over 4 years ago. Updated about 4 years ago.

Status:ClosedStart date:10/22/2020
Priority:NormalDue date:
Assigned To:Knödlseder Jürgen% Done:

100%

Category:-
Target version:2.0.0
Duration:

Description

In case of multi-threading the CPU time is not computed correctly.

For OpenMP, the time needs to be computed using the omp_get_wtime() function, an example is given in the@GObservations::likelihood::eval() method:

Similar code needs to be implemented in @GApplication::celapse(void) and in GApplication::init_members().

Recurrence

No recurrence.

History

#1 Updated by Knödlseder Jürgen over 4 years ago 

    // Timing measurement
    #if defined(G_EVAL_TIMING)
    #ifdef _OPENMP
    double t_start = omp_get_wtime();
    #else
    clock_t t_start = clock();
    #endif
    #endif
    ...
    // Timing measurement
    #if defined(G_EVAL_TIMING)
    #ifdef _OPENMP
    double t_elapse = omp_get_wtime()-t_start;
    #else
    double t_elapse = (double)(clock() - t_start) / (double)CLOCKS_PER_SEC;
    #endif
    std::cout << "GObservations::optimizer::eval: CPU usage = " 
              << t_elapse << " sec" << std::endl;
    #endif

#2 Updated by Knödlseder Jürgen over 4 years ago

  • Status changed from New to Feedback
  • Assigned To set to Knödlseder Jürgen
  • % Done changed from 0 to 90

I implemented the change and merged the code into devel. It remains to be seen on a system that actually uses OpenMP whether the CPU time is not computed corrected. I therefore keep the issue status on Feedback.

#3 Updated by Knödlseder Jürgen about 4 years ago

  • Status changed from Feedback to Closed
  • % Done changed from 90 to 100

The times are now correct.

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