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1 | /* Copyright (C) 2010 Pierre-Marc Fournier |
2 | * | |
3 | * This library is free software; you can redistribute it and/or | |
4 | * modify it under the terms of the GNU Lesser General Public | |
5 | * License as published by the Free Software Foundation; either | |
6 | * version 2.1 of the License, or (at your option) any later version. | |
7 | * | |
8 | * This library is distributed in the hope that it will be useful, | |
9 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
11 | * Lesser General Public License for more details. | |
12 | * | |
13 | * You should have received a copy of the GNU Lesser General Public | |
14 | * License along with this library; if not, write to the Free Software | |
15 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
16 | */ | |
17 | ||
9c6bb081 JD |
18 | #ifndef _UST_CLOCK_H |
19 | #define _UST_CLOCK_H | |
518d7abb | 20 | |
ca4525b5 | 21 | #include <time.h> |
518d7abb PMF |
22 | #include <sys/time.h> |
23 | #include <ust/kcompat/kcompat.h> | |
24 | ||
25 | /* TRACE CLOCK */ | |
26 | ||
27 | /* There are two types of clocks that can be used. | |
28 | - TSC based clock | |
29 | - gettimeofday() clock | |
30 | ||
31 | Microbenchmarks on Linux 2.6.30 on Core2 Duo 3GHz (functions are inlined): | |
9c6bb081 JD |
32 | Calls (100000000) to tsc(): 4004035641 cycles or 40 cycles/call |
33 | Calls (100000000) to gettimeofday(): 9723158352 cycles or 97 cycles/call | |
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34 | |
35 | For merging traces with the kernel, a time source compatible with that of | |
36 | the kernel is necessary. | |
37 | ||
ca4525b5 PMF |
38 | Instead of gettimeofday(), we are now using clock_gettime for better |
39 | precision and monotonicity. | |
518d7abb PMF |
40 | */ |
41 | ||
9c6bb081 JD |
42 | #if __i386__ || __x86_64__ |
43 | /* Only available for x86 arch */ | |
44 | #define CLOCK_TRACE_FREQ 14 | |
45 | #define CLOCK_TRACE 15 | |
46 | union lttng_timespec { | |
ca4525b5 | 47 | struct timespec ts; |
9c6bb081 JD |
48 | u64 lttng_ts; |
49 | }; | |
50 | #endif /* __i386__ || __x86_64__ */ | |
518d7abb | 51 | |
08b070db | 52 | extern int ust_clock_source; |
518d7abb | 53 | |
9c6bb081 JD |
54 | /* Choosing correct trace clock */ |
55 | #if __PPC__ | |
518d7abb PMF |
56 | static __inline__ u64 trace_clock_read64(void) |
57 | { | |
58 | unsigned long tb_l; | |
59 | unsigned long tb_h; | |
60 | unsigned long tb_h2; | |
61 | u64 tb; | |
62 | ||
63 | __asm__ ( | |
64 | "1:\n\t" | |
65 | "mftbu %[rhigh]\n\t" | |
66 | "mftb %[rlow]\n\t" | |
67 | "mftbu %[rhigh2]\n\t" | |
68 | "cmpw %[rhigh],%[rhigh2]\n\t" | |
69 | "bne 1b\n\t" | |
9c6bb081 JD |
70 | : [rhigh] "=r" (tb_h), [rhigh2] "=r" (tb_h2), [rlow] "=r" (tb_l)); |
71 | ||
518d7abb PMF |
72 | tb = tb_h; |
73 | tb <<= 32; | |
74 | tb |= tb_l; | |
75 | ||
76 | return tb; | |
77 | } | |
78 | ||
9c6bb081 | 79 | #else /* !__PPC__ */ |
518d7abb | 80 | |
9c6bb081 JD |
81 | static __inline__ u64 trace_clock_read64(void) |
82 | { | |
83 | struct timespec ts; | |
84 | u64 retval; | |
85 | union lttng_timespec *lts = (union lttng_timespec *) &ts; | |
86 | ||
87 | clock_gettime(ust_clock_source, &ts); | |
88 | /* | |
89 | * Clock source can change when loading the binary (tracectl.c) | |
90 | * so we must check if the clock source has changed before | |
91 | * returning the correct value | |
92 | */ | |
93 | if (likely(ust_clock_source == CLOCK_TRACE)) { | |
94 | retval = lts->lttng_ts; | |
95 | } else { /* CLOCK_MONOTONIC */ | |
96 | retval = ts.tv_sec; | |
97 | retval *= 1000000000; | |
98 | retval += ts.tv_nsec; | |
99 | } | |
100 | ||
101 | return retval; | |
102 | } | |
103 | ||
104 | #endif /* __PPC__ */ | |
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105 | |
106 | static __inline__ u64 trace_clock_frequency(void) | |
107 | { | |
9c6bb081 JD |
108 | struct timespec ts; |
109 | union lttng_timespec *lts = (union lttng_timespec *) &ts; | |
110 | ||
111 | if (likely(ust_clock_source == CLOCK_TRACE)) { | |
112 | clock_gettime(CLOCK_TRACE_FREQ, &ts); | |
113 | return lts->lttng_ts; | |
114 | } | |
ca4525b5 | 115 | return 1000000000LL; |
518d7abb PMF |
116 | } |
117 | ||
118 | static __inline__ u32 trace_clock_freq_scale(void) | |
119 | { | |
120 | return 1; | |
121 | } | |
122 | ||
9c6bb081 | 123 | #endif /* _UST_CLOCK_H */ |