1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
|
/*
* Copyright (c) 2022 Cisco Systems, Inc. All rights reserved.
* $COPYRIGHT$
*
* Additional copyrights may follow
*
* $HEADER$
*/
/** @file clock_gettime.h
*
* Simple, portable wrappers around clock_gettime(3) and
* clock_getres(3) to always get monotonically-increasing time.
*
* If the underlying OS does not have clock_gettime(3), use
* gettimeofday(3) instead.
*
* We intentionally do not use the OPAL timer framework for
* high-prevision time here; see
* https://github.com/open-mpi/ompi/issues/3003 for more details.
*
* As of Dec 2021, it turns out that CLOCK_MONOTONIC can actually go
* backwards on macOS (!). CLOCK_MONOTONIC does *not* go backwards on
* Linux (or anywhere else we can find), though, even in the presence
* of small NTP time adjustments -- e.g., adjtime(3) simply slightly
* speeds up or slows down the system clock to make it eventually get
* to the desired time. On macOS, we can use CLOCK_MONOTONIC_RAW,
* which never goes backwards.
*
* Hence, for these wrappers, use CLOCK_MONOTONIC_RAW on Darwin, and
* use CLOCK_MONOTONIC everywhere else.
*
* See
* https://github.com/open-mpi/ompi/pull/8057#discussion_r762612710
* and
* https://github.com/open-mpi/ompi/pull/8057#discussion_r762618783
* for more details.
*/
#ifndef OPAL_UTIL_CLOCK_GETTIME_H_
#define OPAL_UTIL_CLOCK_GETTIME_H_
#include "opal_config.h"
#if HAVE_TIME_H
#include <time.h>
#endif
#if HAVE_SYS_TIME_H
#include <sys/time.h>
#endif
#if OPAL_HAVE_CLOCK_GETTIME
#if defined(__darwin__)
#define OPAL_CLOCK_TYPE CLOCK_MONOTONIC_RAW
#else
#define OPAL_CLOCK_TYPE CLOCK_MONOTONIC
#endif
#endif // OPAL_HAVE_CLOCK_GETTIME
#if !defined(HAVE_STRUCT_TIMESPEC_TV_NSEC)
// Make sure that we have struct timespec; if not, define it.
struct timespec {
time_t tv_sec;
long tv_nsec;
};
#endif
/**
* Simple, portable wrapper around clock_gettime(3) for high-precision time.
*
* If the underlying system does not have clock_gettime(3), use
* gettimeofday(3) instead.
*
* @param spec (OUT) Struct to return the time
* @return Return value from underlying clock_gettime()
*/
static inline int opal_clock_gettime(struct timespec *spec)
{
#if OPAL_HAVE_CLOCK_GETTIME
return clock_gettime(OPAL_CLOCK_TYPE, spec);
#else
// If we do not have clock_gettime(), fall back to gettimeofday()
struct timeval tv;
int ret = gettimeofday(&tv, NULL);
spec->tv_sec = tv.tv_sec;
// Elevate the micrseconds to nanoseconds
spec->tv_nsec = tv.tv_usec * 1000;
return ret;
#endif
}
/**
* Simple, portable wrapper around clock_getres(3) for high-precision time.
*
* If the underlying system does not have clock_gettime(3), return usec
* precision (because opal_clock_gettime() will be using gettimeofday(3)).
*
* @param spec (OUT) Struct to return the resolution
* @return Return value from underlying clock_getres()
*/
static inline int opal_clock_getres(struct timespec *spec)
{
#if OPAL_HAVE_CLOCK_GETTIME
return clock_getres(OPAL_CLOCK_TYPE, spec);
#else
// If we don't have clock_gettime(), just return usec precision.
spec->tv_sec = 0;
spec->tv_nsec = 1000;
return 0;
#endif
}
#endif // OPAL_UTIL_CLOCK_GETTIME_H_
|
