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1 | // Copyright Contributors to the OpenVDB Project | ||
2 | // SPDX-License-Identifier: MPL-2.0 | ||
3 | |||
4 | #ifndef OPENVDB_UTIL_CPUTIMER_HAS_BEEN_INCLUDED | ||
5 | #define OPENVDB_UTIL_CPUTIMER_HAS_BEEN_INCLUDED | ||
6 | |||
7 | #include <openvdb/version.h> | ||
8 | #include <string> | ||
9 | #include <chrono> | ||
10 | #include <iostream>// for std::cerr | ||
11 | #include <sstream>// for ostringstream | ||
12 | #include <iomanip>// for setprecision | ||
13 | #include "Formats.h"// for printTime | ||
14 | |||
15 | namespace openvdb { | ||
16 | OPENVDB_USE_VERSION_NAMESPACE | ||
17 | namespace OPENVDB_VERSION_NAME { | ||
18 | namespace util { | ||
19 | |||
20 | /// @brief Simple timer for basic profiling. | ||
21 | /// | ||
22 | /// @code | ||
23 | /// util::CpuTimer timer; | ||
24 | /// // code here will not be timed! | ||
25 | /// timer.start("algorithm"); | ||
26 | /// // code to be timed goes here | ||
27 | /// timer.stop(); | ||
28 | /// @endcode | ||
29 | /// | ||
30 | /// or to time multiple blocks of code | ||
31 | /// | ||
32 | /// @code | ||
33 | /// util::CpuTimer timer("algorithm 1"); | ||
34 | /// // code to be timed goes here | ||
35 | /// timer.restart("algorithm 2"); | ||
36 | /// // code to be timed goes here | ||
37 | /// timer.stop(); | ||
38 | /// @endcode | ||
39 | /// | ||
40 | /// or to measure speedup between multiple runs | ||
41 | /// | ||
42 | /// @code | ||
43 | /// util::CpuTimer timer("algorithm 1"); | ||
44 | /// // code for the first run goes here | ||
45 | /// const double t1 = timer.restart("algorithm 2"); | ||
46 | /// // code for the second run goes here | ||
47 | /// const double t2 = timer.stop(); | ||
48 | /// std::cerr << "Algorithm 1 is " << (t2/t1) | ||
49 | /// << " timers faster than algorithm 2\n"; | ||
50 | /// @endcode | ||
51 | /// | ||
52 | /// or to measure multiple blocks of code with deferred output | ||
53 | /// | ||
54 | /// @code | ||
55 | /// util::CpuTimer timer(); | ||
56 | /// // code here will not be timed! | ||
57 | /// timer.start(); | ||
58 | /// // code for the first run goes here | ||
59 | /// const double t1 = timer.restart();//time in milliseconds | ||
60 | /// // code for the second run goes here | ||
61 | /// const double t2 = timer.restart();//time in milliseconds | ||
62 | /// // code here will not be timed! | ||
63 | /// util::printTime(std::cout, t1, "Algorithm 1 completed in "); | ||
64 | /// util::printTime(std::cout, t2, "Algorithm 2 completed in "); | ||
65 | /// @endcode | ||
66 | class CpuTimer | ||
67 | { | ||
68 | public: | ||
69 | /// @brief Initiate timer | ||
70 |
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3 | CpuTimer(std::ostream& os = std::cerr) : mOutStream(os), mT0(this->now()) {} |
71 | |||
72 | /// @brief Prints message and start timer. | ||
73 | /// | ||
74 | /// @note Should normally be followed by a call to stop() | ||
75 | CpuTimer(const std::string& msg, std::ostream& os = std::cerr) : mOutStream(os) { this->start(msg); } | ||
76 | |||
77 | /// @brief Start timer. | ||
78 | /// | ||
79 | /// @note Should normally be followed by a call to milliseconds() or stop(std::string) | ||
80 | 250 | inline void start() { mT0 = this->now(); } | |
81 | |||
82 | /// @brief Print message and start timer. | ||
83 | /// | ||
84 | /// @note Should normally be followed by a call to stop() | ||
85 | inline void start(const std::string& msg) | ||
86 | { | ||
87 | mOutStream << msg << " ..."; | ||
88 | this->start(); | ||
89 | } | ||
90 | |||
91 | /// @brief Return Time difference in microseconds since construction or start was called. | ||
92 | /// | ||
93 | /// @note Combine this method with start() to get timing without any outputs. | ||
94 | inline int64_t microseconds() const | ||
95 | { | ||
96 | 248 | return (this->now() - mT0); | |
97 | } | ||
98 | |||
99 | /// @brief Return Time difference in milliseconds since construction or start was called. | ||
100 | /// | ||
101 | /// @note Combine this method with start() to get timing without any outputs. | ||
102 | inline double milliseconds() const | ||
103 | { | ||
104 | static constexpr double resolution = 1.0 / 1E3; | ||
105 |
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250 | return static_cast<double>(this->microseconds()) * resolution; |
106 | } | ||
107 | |||
108 | /// @brief Return Time difference in seconds since construction or start was called. | ||
109 | /// | ||
110 | /// @note Combine this method with start() to get timing without any outputs. | ||
111 | inline double seconds() const | ||
112 | { | ||
113 | static constexpr double resolution = 1.0 / 1E6; | ||
114 | return static_cast<double>(this->microseconds()) * resolution; | ||
115 | } | ||
116 | |||
117 | inline std::string time() const | ||
118 | { | ||
119 | const double msec = this->milliseconds(); | ||
120 | std::ostringstream os; | ||
121 | printTime(os, msec, "", "", 4, 1, 1); | ||
122 | return os.str(); | ||
123 | } | ||
124 | |||
125 | /// @brief Returns and prints time in milliseconds since construction or start was called. | ||
126 | /// | ||
127 | /// @note Combine this method with start(std::string) to print at start and stop of task being timed. | ||
128 | inline double stop() const | ||
129 | { | ||
130 | const double msec = this->milliseconds(); | ||
131 | printTime(mOutStream, msec, " completed in ", "\n", 4, 3, 1); | ||
132 | return msec; | ||
133 | } | ||
134 | |||
135 | /// @brief Returns and prints time in milliseconds since construction or start was called. | ||
136 | /// | ||
137 | /// @note Combine this method with start() to delay output of task being timed. | ||
138 | inline double stop(const std::string& msg) const | ||
139 | { | ||
140 | const double msec = this->milliseconds(); | ||
141 | mOutStream << msg << " ..."; | ||
142 | printTime(mOutStream, msec, " completed in ", "\n", 4, 3, 1); | ||
143 | return msec; | ||
144 | } | ||
145 | |||
146 | /// @brief Re-start timer. | ||
147 | /// @return time in milliseconds since previous start or restart. | ||
148 | /// | ||
149 | /// @note Should normally be followed by a call to stop() or restart() | ||
150 | 2 | inline double restart() | |
151 | { | ||
152 | const double msec = this->milliseconds(); | ||
153 | this->start(); | ||
154 | 2 | return msec; | |
155 | } | ||
156 | |||
157 | /// @brief Stop previous timer, print message and re-start timer. | ||
158 | /// @return time in milliseconds since previous start or restart. | ||
159 | /// | ||
160 | /// @note Should normally be followed by a call to stop() or restart() | ||
161 | inline double restart(const std::string& msg) | ||
162 | { | ||
163 | const double delta = this->stop(); | ||
164 | this->start(msg); | ||
165 | return delta; | ||
166 | } | ||
167 | |||
168 | private: | ||
169 | 501 | static int64_t now() | |
170 | { | ||
171 | // steady_clock is a monotonically increasing clock designed for timing duration | ||
172 | // note that high_resolution_clock is aliased to either steady_clock or system_clock | ||
173 | // depending on the platform, so it is preferrable to use steady_clock | ||
174 | const auto time_since_epoch = | ||
175 | 501 | std::chrono::steady_clock::now().time_since_epoch(); | |
176 | // cast time since epoch into microseconds (1 / 1000000 seconds) | ||
177 | const auto microseconds = | ||
178 | std::chrono::duration_cast<std::chrono::microseconds>(time_since_epoch).count(); | ||
179 | // cast to a a 64-bit signed integer as this will overflow in 2262! | ||
180 | 501 | return static_cast<int64_t>(microseconds); | |
181 | } | ||
182 | |||
183 | std::ostream& mOutStream; | ||
184 | int64_t mT0{0}; | ||
185 | };// CpuTimer | ||
186 | |||
187 | } // namespace util | ||
188 | } // namespace OPENVDB_VERSION_NAME | ||
189 | } // namespace openvdb | ||
190 | |||
191 | |||
192 | #endif // OPENVDB_UTIL_CPUTIMER_HAS_BEEN_INCLUDED | ||
193 |