Actual source code: cputime.c

petsc-3.8.0 2017-09-26
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  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