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pg_rusage.c
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1 /*-------------------------------------------------------------------------
2  *
3  * pg_rusage.c
4  * Resource usage measurement support routines.
5  *
6  *
7  * Portions Copyright (c) 1996-2017, 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
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 *
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 }
int gettimeofday(struct timeval *tp, struct timezone *tzp)
Definition: gettimeofday.c:105
return result
Definition: formatting.c:1632
int snprintf(char *str, size_t count, const char *fmt,...) pg_attribute_printf(3
struct timeval ru_stime
Definition: rusagestub.h:29
int getrusage(int who, struct rusage *rusage)
Definition: getrusage.c:31
void pg_rusage_init(PGRUsage *ru0)
Definition: pg_rusage.c:27
struct timeval tv
Definition: pg_rusage.h:29
const char * pg_rusage_show(const PGRUsage *ru0)
Definition: pg_rusage.c:40
struct rusage ru
Definition: pg_rusage.h:30
struct timeval ru_utime
Definition: rusagestub.h:28
#define RUSAGE_SELF
Definition: rusagestub.h:23
#define NULL
Definition: c.h:229