1 /*-------------------------------------------------------------------------
2 *
3 * pg_rusage.c
4 * Resource usage measurement support routines.
5 *
6 *
7 * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
8 * Portions Copyright (c) 1994, Regents of the University of California
9 *
10 *
11 * IDENTIFICATION
12 * src/backend/utils/misc/pg_rusage.c
13 *
14 *-------------------------------------------------------------------------
15 */
16 #include "postgres.h"
17
18 #include <unistd.h>
19
20 #include "utils/pg_rusage.h"
21
22
23 /*
24 * Initialize usage snapshot.
25 */
26 void
pg_rusage_init(PGRUsage * ru0)27 pg_rusage_init(PGRUsage *ru0)
28 {
29 getrusage(RUSAGE_SELF, &ru0->ru);
30 gettimeofday(&ru0->tv, NULL);
31 }
32
33 /*
34 * Compute elapsed time since ru0 usage snapshot, and format into
35 * a displayable string. Result is in a static string, which is
36 * tacky, but no one ever claimed that the Postgres backend is
37 * threadable...
38 */
39 const char *
pg_rusage_show(const PGRUsage * ru0)40 pg_rusage_show(const PGRUsage *ru0)
41 {
42 static char result[100];
43 PGRUsage ru1;
44
45 pg_rusage_init(&ru1);
46
47 if (ru1.tv.tv_usec < ru0->tv.tv_usec)
48 {
49 ru1.tv.tv_sec--;
50 ru1.tv.tv_usec += 1000000;
51 }
52 if (ru1.ru.ru_stime.tv_usec < ru0->ru.ru_stime.tv_usec)
53 {
54 ru1.ru.ru_stime.tv_sec--;
55 ru1.ru.ru_stime.tv_usec += 1000000;
56 }
57 if (ru1.ru.ru_utime.tv_usec < ru0->ru.ru_utime.tv_usec)
58 {
59 ru1.ru.ru_utime.tv_sec--;
60 ru1.ru.ru_utime.tv_usec += 1000000;
61 }
62
63 snprintf(result, sizeof(result),
64 _("CPU: user: %d.%02d s, system: %d.%02d s, elapsed: %d.%02d s"),
65 (int) (ru1.ru.ru_utime.tv_sec - ru0->ru.ru_utime.tv_sec),
66 (int) (ru1.ru.ru_utime.tv_usec - ru0->ru.ru_utime.tv_usec) / 10000,
67 (int) (ru1.ru.ru_stime.tv_sec - ru0->ru.ru_stime.tv_sec),
68 (int) (ru1.ru.ru_stime.tv_usec - ru0->ru.ru_stime.tv_usec) / 10000,
69 (int) (ru1.tv.tv_sec - ru0->tv.tv_sec),
70 (int) (ru1.tv.tv_usec - ru0->tv.tv_usec) / 10000);
71
72 return result;
73 }
74