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d0b96690 DG |
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> | |
fc0bb9fa MD |
28 | #include <urcu/system.h> |
29 | #include <urcu/arch.h> | |
30 | #include <lttng/ust-clock.h> | |
d0b96690 DG |
31 | |
32 | #include <common/compat/uuid.h> | |
33 | ||
34 | /* TRACE CLOCK */ | |
35 | ||
fc0bb9fa MD |
36 | struct 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 | ||
44 | extern struct lttng_trace_clock *lttng_trace_clock; | |
45 | ||
46 | void lttng_ust_clock_init(void); | |
47 | ||
d0b96690 DG |
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 | ||
55 | static __inline__ | |
fc0bb9fa | 56 | uint64_t trace_clock_read64_monotonic(void) |
d0b96690 DG |
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 | ||
64 | static __inline__ | |
fc0bb9fa | 65 | uint64_t trace_clock_freq_monotonic(void) |
d0b96690 DG |
66 | { |
67 | return 1000000000ULL; | |
68 | } | |
69 | ||
70 | static __inline__ | |
fc0bb9fa | 71 | int trace_clock_uuid_monotonic(char *uuid) |
d0b96690 DG |
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 | } | |
fc0bb9fa MD |
86 | len = fread(uuid, 1, LTTNG_UST_UUID_STR_LEN - 1, fp); |
87 | if (len < LTTNG_UST_UUID_STR_LEN - 1) { | |
d0b96690 DG |
88 | ret = -EINVAL; |
89 | goto end; | |
90 | } | |
fc0bb9fa | 91 | uuid[LTTNG_UST_UUID_STR_LEN - 1] = '\0'; |
d0b96690 DG |
92 | end: |
93 | fclose(fp); | |
94 | return ret; | |
95 | } | |
96 | ||
fc0bb9fa MD |
97 | static __inline__ |
98 | const char *trace_clock_name_monotonic(void) | |
99 | { | |
100 | return "monotonic"; | |
101 | } | |
102 | ||
103 | static __inline__ | |
104 | const char *trace_clock_description_monotonic(void) | |
105 | { | |
106 | return "Monotonic Clock"; | |
107 | } | |
108 | ||
109 | static __inline__ | |
110 | uint64_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 | ||
122 | static __inline__ | |
123 | uint64_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 | ||
135 | static __inline__ | |
136 | int 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 | ||
149 | static __inline__ | |
150 | const 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 | ||
162 | static __inline__ | |
163 | const 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 */ |