xref: /petsc/src/sys/time/cputime.c (revision c094ef4021e955ef5f85f7d8a1bbc6ed64ba7621)
1 
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 */
6 
7 #include <petscsys.h>                       /*I "petscsys.h" I*/
8 #include <petsctime.h>                      /*I "petsctime.h" I*/
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
20 
21 #if defined(PETSC_HAVE_SYS_TIMES_H)
22 
23 #include <sys/times.h>
24 #undef __FUNCT__
25 #define __FUNCT__ "PetscGetCPUTime"
26 PetscErrorCode  PetscGetCPUTime(PetscLogDouble *t)
27 {
28   struct tms temp;
29 
30   PetscFunctionBegin;
31   times(&temp);
32   *t = ((double)temp.tms_utime)/((double)CLOCKS_PER_SEC);
33   PetscFunctionReturn(0);
34 }
35 
36 #elif defined(PETSC_HAVE_CLOCK)
37 
38 #include <time.h>
39 
40 #undef __FUNCT__
41 #define __FUNCT__ "PetscGetCPUTime"
42 PetscErrorCode  PetscGetCPUTime(PetscLogDouble *t)
43 {
44   PetscFunctionBegin;
45   *t = ((double)clock()) / ((double)CLOCKS_PER_SEC);
46   PetscFunctionReturn(0);
47 }
48 
49 #else
50 
51 #include <sys/time.h>
52 #include <sys/resource.h>
53 
54 #undef __FUNCT__
55 #define __FUNCT__ "PetscGetCPUTime"
56 /*@
57     PetscGetCPUTime - Returns the CPU time in seconds used by the process.
58 
59     Not Collective
60 
61     Output Parameter:
62 .   t - Time in seconds charged to the process.
63 
64     Example:
65 .vb
66     #include <petscsys.h>
67     ...
68     PetscLogDouble t1, t2;
69 
70     ierr = PetscGetCPUTime(&t1);CHKERRQ(ierr);
71     ... code to time ...
72     ierr = PetscGetCPUTime(&t2);CHKERRQ(ierr);
73     printf("Code took %f CPU seconds\n", t2-t1);
74 .ve
75 
76     Level: intermediate
77 
78     Notes:
79     One should use PetscTime() or the -log_summary option of
80     PETSc for profiling. The CPU time is NOT a realistic number to
81     use since it does not include the time for message passing etc.
82     Also on many systems the accuracy is only on the order of microseconds.
83 @*/
84 PetscErrorCode  PetscGetCPUTime(PetscLogDouble *t)
85 {
86   static struct rusage temp;
87   PetscLogDouble       foo,foo1;
88 
89   PetscFunctionBegin;
90   getrusage(RUSAGE_SELF,&temp);
91   foo  = temp.ru_utime.tv_sec;        /* seconds */
92   foo1 = temp.ru_utime.tv_usec;       /* uSecs */
93   *t   = foo + foo1 * 1.0e-6;
94   PetscFunctionReturn(0);
95 }
96 
97 #endif
98