GCC Code Coverage Report


Directory: ./
File: openvdb/openvdb/util/CpuTimer.h
Date: 2022-07-25 17:40:05
Exec Total Coverage
Lines: 9 9 100.0%
Functions: 2 2 100.0%
Branches: 3 4 75.0%

Line Branch Exec Source
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