Fix: mark ltt_sessions_ht_destroy as static
[lttng-tools.git] / src / bin / lttng-sessiond / ust-clock.h
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1/*
2 * Copyright (C) 2010 Pierre-Marc Fournier
3 * Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
4 *
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Lesser General Public
7 * License as published by the Free Software Foundation; version 2.1 of
8 * the License.
9 *
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Lesser General Public License for more details.
14 *
15 * You should have received a copy of the GNU Lesser General Public
16 * License along with this library; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
18 */
19
20#ifndef _UST_CLOCK_H
21#define _UST_CLOCK_H
22
23#include <time.h>
24#include <sys/time.h>
25#include <stdint.h>
26#include <stddef.h>
27#include <stdio.h>
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28#include <urcu/system.h>
29#include <urcu/arch.h>
30#include <lttng/ust-clock.h>
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31
32#include <common/compat/uuid.h>
33
34/* TRACE CLOCK */
35
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36struct lttng_trace_clock {
37 uint64_t (*read64)(void);
38 uint64_t (*freq)(void);
39 int (*uuid)(char *uuid);
40 const char *(*name)(void);
41 const char *(*description)(void);
42};
43
44extern struct lttng_trace_clock *lttng_trace_clock;
45
46void lttng_ust_clock_init(void);
47
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48/*
49 * Currently using the kernel MONOTONIC clock, waiting for kernel-side
50 * LTTng to implement mmap'd trace clock.
51 */
52
53/* Choosing correct trace clock */
54
55static __inline__
fc0bb9fa 56uint64_t trace_clock_read64_monotonic(void)
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57{
58 struct timespec ts;
59
60 clock_gettime(CLOCK_MONOTONIC, &ts);
61 return ((uint64_t) ts.tv_sec * 1000000000ULL) + ts.tv_nsec;
62}
63
64static __inline__
fc0bb9fa 65uint64_t trace_clock_freq_monotonic(void)
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66{
67 return 1000000000ULL;
68}
69
70static __inline__
fc0bb9fa 71int trace_clock_uuid_monotonic(char *uuid)
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72{
73 int ret = 0;
74 size_t len;
75 FILE *fp;
76
77 /*
78 * boot_id needs to be read once before being used concurrently
79 * to deal with a Linux kernel race. A fix is proposed for
80 * upstream, but the work-around is needed for older kernels.
81 */
82 fp = fopen("/proc/sys/kernel/random/boot_id", "r");
83 if (!fp) {
84 return -ENOENT;
85 }
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86 len = fread(uuid, 1, LTTNG_UST_UUID_STR_LEN - 1, fp);
87 if (len < LTTNG_UST_UUID_STR_LEN - 1) {
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88 ret = -EINVAL;
89 goto end;
90 }
fc0bb9fa 91 uuid[LTTNG_UST_UUID_STR_LEN - 1] = '\0';
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92end:
93 fclose(fp);
94 return ret;
95}
96
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97static __inline__
98const char *trace_clock_name_monotonic(void)
99{
100 return "monotonic";
101}
102
103static __inline__
104const char *trace_clock_description_monotonic(void)
105{
106 return "Monotonic Clock";
107}
108
109static __inline__
110uint64_t trace_clock_read64(void)
111{
112 struct lttng_trace_clock *ltc = CMM_LOAD_SHARED(lttng_trace_clock);
113
114 if (caa_likely(!ltc)) {
115 return trace_clock_read64_monotonic();
116 } else {
117 cmm_read_barrier_depends(); /* load ltc before content */
118 return ltc->read64();
119 }
120}
121
122static __inline__
123uint64_t trace_clock_freq(void)
124{
125 struct lttng_trace_clock *ltc = CMM_LOAD_SHARED(lttng_trace_clock);
126
127 if (!ltc) {
128 return trace_clock_freq_monotonic();
129 } else {
130 cmm_read_barrier_depends(); /* load ltc before content */
131 return ltc->freq();
132 }
133}
134
135static __inline__
136int trace_clock_uuid(char *uuid)
137{
138 struct lttng_trace_clock *ltc = CMM_LOAD_SHARED(lttng_trace_clock);
139
140 cmm_read_barrier_depends(); /* load ltc before content */
141 /* Use default UUID cb when NULL */
142 if (!ltc || !ltc->uuid) {
143 return trace_clock_uuid_monotonic(uuid);
144 } else {
145 return ltc->uuid(uuid);
146 }
147}
148
149static __inline__
150const char *trace_clock_name(void)
151{
152 struct lttng_trace_clock *ltc = CMM_LOAD_SHARED(lttng_trace_clock);
153
154 if (!ltc) {
155 return trace_clock_name_monotonic();
156 } else {
157 cmm_read_barrier_depends(); /* load ltc before content */
158 return ltc->name();
159 }
160}
161
162static __inline__
163const char *trace_clock_description(void)
164{
165 struct lttng_trace_clock *ltc = CMM_LOAD_SHARED(lttng_trace_clock);
166
167 if (!ltc) {
168 return trace_clock_description_monotonic();
169 } else {
170 cmm_read_barrier_depends(); /* load ltc before content */
171 return ltc->description();
172 }
173}
174
d0b96690 175#endif /* _UST_CLOCK_H */
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