Actual source code: cputime.c
petsc-3.10.5 2019-03-28
Report Typos and Errors

      2: /*
      3:   This is to allow one to measure CPU time usage of their job,
      4:   NOT real time usage. Do not use this for reported timings, speedup etc.
      5: */

      7:  #include <petscsys.h>
      8:  #include <petsctime.h>
      9: #include <ctype.h>
     10: #include <sys/stat.h>
     11: #if defined(PETSC_HAVE_SYS_UTSNAME_H)
     12: #include <sys/utsname.h>
     13: #endif
     14: #if defined(PETSC_HAVE_TIME_H)
     15: #include <time.h>
     16: #endif
     17: #if defined(PETSC_HAVE_SYS_SYSTEMINFO_H)
     18: #include <sys/systeminfo.h>
     19: #endif

     21: #if defined(PETSC_HAVE_SYS_TIMES_H)

     23: #include <sys/times.h>
     24: PetscErrorCode  PetscGetCPUTime(PetscLogDouble *t)
     25: {
     26:   struct tms temp;

     29:   times(&temp);
     30:   *t = ((double)temp.tms_utime)/((double)CLOCKS_PER_SEC);
     31:   return(0);
     32: }

     34: #elif defined(PETSC_HAVE_CLOCK)

     36: #include <time.h>

     38: PetscErrorCode  PetscGetCPUTime(PetscLogDouble *t)
     39: {
     41:   *t = ((double)clock()) / ((double)CLOCKS_PER_SEC);
     42:   return(0);
     43: }

     45: #else

     47: #include <sys/time.h>
     48: #include <sys/resource.h>

     50: /*@
     51:     PetscGetCPUTime - Returns the CPU time in seconds used by the process.

     53:     Not Collective

     55:     Output Parameter:
     56: .   t - Time in seconds charged to the process.

     58:     Example:
     59: .vb
     60:     #include <petscsys.h>
     61:     ...
     62:     PetscLogDouble t1, t2;

     64:     PetscGetCPUTime(&t1);
     65:     ... code to time ...
     66:     PetscGetCPUTime(&t2);
     67:     printf("Code took %f CPU seconds\n", t2-t1);
     68: .ve

     70:     Level: intermediate

     72:     Notes:
     73:     One should use PetscTime() or the -log_view option of
     74:     PETSc for profiling. The CPU time is NOT a realistic number to
     75:     use since it does not include the time for message passing etc.
     76:     Also on many systems the accuracy is only on the order of microseconds.
     77: @*/
     78: PetscErrorCode  PetscGetCPUTime(PetscLogDouble *t)
     79: {
     80:   static struct rusage temp;
     81:   PetscLogDouble       foo,foo1;

     84:   getrusage(RUSAGE_SELF,&temp);
     85:   foo  = temp.ru_utime.tv_sec;        /* seconds */
     86:   foo1 = temp.ru_utime.tv_usec;       /* uSecs */
     87:   *t   = foo + foo1 * 1.0e-6;
     88:   return(0);
     89: }

     91: #endif