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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 | ||
18 | #ifndef UST_CLOCK_H | |
19 | #define UST_CLOCK_H | |
20 | ||
ca4525b5 | 21 | #include <time.h> |
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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): | |
32 | Calls (100000000) to tsc(): 4004035641 cycles or 40 cycles/call | |
33 | Calls (100000000) to gettimeofday(): 9723158352 cycles or 97 cycles/call | |
34 | ||
35 | For merging traces with the kernel, a time source compatible with that of | |
36 | the kernel is necessary. | |
37 | ||
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38 | Instead of gettimeofday(), we are now using clock_gettime for better |
39 | precision and monotonicity. | |
40 | ||
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41 | */ |
42 | ||
43 | #define TRACE_CLOCK_GENERIC | |
44 | #ifdef TRACE_CLOCK_GENERIC | |
45 | ||
46 | static __inline__ u64 trace_clock_read64(void) | |
47 | { | |
ca4525b5 | 48 | struct timespec ts; |
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49 | u64 retval; |
50 | ||
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51 | clock_gettime(CLOCK_MONOTONIC, &ts); |
52 | retval = ts.tv_sec; | |
53 | retval *= 1000000000; | |
54 | retval += ts.tv_nsec; | |
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55 | |
56 | return retval; | |
57 | } | |
58 | ||
59 | #else | |
60 | ||
61 | #if __i386 || __x86_64 | |
62 | ||
63 | /* WARNING: Make sure to set frequency and scaling functions that will not | |
64 | * result in lttv timestamps (sec.nsec) with seconds greater than 2**32-1. | |
65 | */ | |
66 | static __inline__ u64 trace_clock_read64(void) | |
67 | { | |
68 | uint32_t low; | |
69 | uint32_t high; | |
70 | uint64_t retval; | |
71 | __asm__ volatile ("rdtsc\n" : "=a" (low), "=d" (high)); | |
72 | ||
73 | retval = high; | |
74 | retval <<= 32; | |
75 | return retval | low; | |
76 | } | |
77 | ||
78 | #endif /* __i386 || __x86_64 */ | |
79 | ||
80 | #ifdef __PPC__ | |
81 | ||
82 | static __inline__ u64 trace_clock_read64(void) | |
83 | { | |
84 | unsigned long tb_l; | |
85 | unsigned long tb_h; | |
86 | unsigned long tb_h2; | |
87 | u64 tb; | |
88 | ||
89 | __asm__ ( | |
90 | "1:\n\t" | |
91 | "mftbu %[rhigh]\n\t" | |
92 | "mftb %[rlow]\n\t" | |
93 | "mftbu %[rhigh2]\n\t" | |
94 | "cmpw %[rhigh],%[rhigh2]\n\t" | |
95 | "bne 1b\n\t" | |
96 | : [rhigh] "=r" (tb_h), [rhigh2] "=r" (tb_h2), [rlow] "=r" (tb_l)); | |
97 | ||
98 | tb = tb_h; | |
99 | tb <<= 32; | |
100 | tb |= tb_l; | |
101 | ||
102 | return tb; | |
103 | } | |
104 | ||
105 | #endif /* __PPC__ */ | |
106 | ||
107 | #endif /* ! UST_TRACE_CLOCK_GENERIC */ | |
108 | ||
109 | static __inline__ u64 trace_clock_frequency(void) | |
110 | { | |
ca4525b5 | 111 | return 1000000000LL; |
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112 | } |
113 | ||
114 | static __inline__ u32 trace_clock_freq_scale(void) | |
115 | { | |
116 | return 1; | |
117 | } | |
118 | ||
119 | #endif /* UST_CLOCK_H */ |