1//===-- llvm/Support/Timer.h - Interval Timing Support ----------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#ifndef LLVM_SUPPORT_TIMER_H
10#define LLVM_SUPPORT_TIMER_H
11
12#include "llvm/ADT/StringMap.h"
13#include "llvm/ADT/StringRef.h"
14#include "llvm/Support/DataTypes.h"
15#include <cassert>
16#include <memory>
17#include <string>
18#include <vector>
19
20namespace llvm {
21
22class TimerGroup;
23class raw_ostream;
24
25class TimeRecord {
26 double WallTime = 0.0; ///< Wall clock time elapsed in seconds.
27 double UserTime = 0.0; ///< User time elapsed.
28 double SystemTime = 0.0; ///< System time elapsed.
29 ssize_t MemUsed = 0; ///< Memory allocated (in bytes).
30 uint64_t InstructionsExecuted = 0; ///< Number of instructions executed
31public:
32 TimeRecord() = default;
33
34 /// Get the current time and memory usage. If Start is true we get the memory
35 /// usage before the time, otherwise we get time before memory usage. This
36 /// matters if the time to get the memory usage is significant and shouldn't
37 /// be counted as part of a duration.
38 static TimeRecord getCurrentTime(bool Start = true);
39
40 double getProcessTime() const { return UserTime + SystemTime; }
41 double getUserTime() const { return UserTime; }
42 double getSystemTime() const { return SystemTime; }
43 double getWallTime() const { return WallTime; }
44 ssize_t getMemUsed() const { return MemUsed; }
45 uint64_t getInstructionsExecuted() const { return InstructionsExecuted; }
46
47 bool operator<(const TimeRecord &T) const {
48 // Sort by Wall Time elapsed, as it is the only thing really accurate
49 return WallTime < T.WallTime;
50 }
51
52 void operator+=(const TimeRecord &RHS) {
53 WallTime += RHS.WallTime;
54 UserTime += RHS.UserTime;
55 SystemTime += RHS.SystemTime;
56 MemUsed += RHS.MemUsed;
57 InstructionsExecuted += RHS.InstructionsExecuted;
58 }
59 void operator-=(const TimeRecord &RHS) {
60 WallTime -= RHS.WallTime;
61 UserTime -= RHS.UserTime;
62 SystemTime -= RHS.SystemTime;
63 MemUsed -= RHS.MemUsed;
64 InstructionsExecuted -= RHS.InstructionsExecuted;
65 }
66
67 /// Print the current time record to \p OS, with a breakdown showing
68 /// contributions to the \p Total time record.
69 void print(const TimeRecord &Total, raw_ostream &OS) const;
70};
71
72/// This class is used to track the amount of time spent between invocations of
73/// its startTimer()/stopTimer() methods. Given appropriate OS support it can
74/// also keep track of the RSS of the program at various points. By default,
75/// the Timer will print the amount of time it has captured to standard error
76/// when the last timer is destroyed, otherwise it is printed when its
77/// TimerGroup is destroyed. Timers do not print their information if they are
78/// never started.
79class Timer {
80 TimeRecord Time; ///< The total time captured.
81 TimeRecord StartTime; ///< The time startTimer() was last called.
82 std::string Name; ///< The name of this time variable.
83 std::string Description; ///< Description of this time variable.
84 bool Running = false; ///< Is the timer currently running?
85 bool Triggered = false; ///< Has the timer ever been triggered?
86 TimerGroup *TG = nullptr; ///< The TimerGroup this Timer is in.
87
88 Timer **Prev = nullptr; ///< Pointer to \p Next of previous timer in group.
89 Timer *Next = nullptr; ///< Next timer in the group.
90public:
91 explicit Timer(StringRef TimerName, StringRef TimerDescription) {
92 init(TimerName, TimerDescription);
93 }
94 Timer(StringRef TimerName, StringRef TimerDescription, TimerGroup &tg) {
95 init(TimerName, TimerDescription, tg);
96 }
97 Timer(const Timer &RHS) {
98 assert(!RHS.TG && "Can only copy uninitialized timers");
99 }
100 const Timer &operator=(const Timer &T) {
101 assert(!TG && !T.TG && "Can only assign uninit timers");
102 return *this;
103 }
104 ~Timer();
105
106 /// Create an uninitialized timer, client must use 'init'.
107 explicit Timer() = default;
108 void init(StringRef TimerName, StringRef TimerDescription);
109 void init(StringRef TimerName, StringRef TimerDescription, TimerGroup &tg);
110
111 const std::string &getName() const { return Name; }
112 const std::string &getDescription() const { return Description; }
113 bool isInitialized() const { return TG != nullptr; }
114
115 /// Check if the timer is currently running.
116 bool isRunning() const { return Running; }
117
118 /// Check if startTimer() has ever been called on this timer.
119 bool hasTriggered() const { return Triggered; }
120
121 /// Start the timer running. Time between calls to startTimer/stopTimer is
122 /// counted by the Timer class. Note that these calls must be correctly
123 /// paired.
124 void startTimer();
125
126 /// Stop the timer.
127 void stopTimer();
128
129 /// Clear the timer state.
130 void clear();
131
132 /// Return the duration for which this timer has been running.
133 TimeRecord getTotalTime() const { return Time; }
134
135private:
136 friend class TimerGroup;
137};
138
139/// The TimeRegion class is used as a helper class to call the startTimer() and
140/// stopTimer() methods of the Timer class. When the object is constructed, it
141/// starts the timer specified as its argument. When it is destroyed, it stops
142/// the relevant timer. This makes it easy to time a region of code.
143class TimeRegion {
144 Timer *T;
145 TimeRegion(const TimeRegion &) = delete;
146
147public:
148 explicit TimeRegion(Timer &t) : T(&t) {
149 T->startTimer();
150 }
151 explicit TimeRegion(Timer *t) : T(t) {
152 if (T) T->startTimer();
153 }
154 ~TimeRegion() {
155 if (T) T->stopTimer();
156 }
157};
158
159/// This class is basically a combination of TimeRegion and Timer. It allows
160/// you to declare a new timer, AND specify the region to time, all in one
161/// statement. All timers with the same name are merged. This is primarily
162/// used for debugging and for hunting performance problems.
163struct NamedRegionTimer : public TimeRegion {
164 explicit NamedRegionTimer(StringRef Name, StringRef Description,
165 StringRef GroupName,
166 StringRef GroupDescription, bool Enabled = true);
167};
168
169/// The TimerGroup class is used to group together related timers into a single
170/// report that is printed when the TimerGroup is destroyed. It is illegal to
171/// destroy a TimerGroup object before all of the Timers in it are gone. A
172/// TimerGroup can be specified for a newly created timer in its constructor.
173class TimerGroup {
174 struct PrintRecord {
175 TimeRecord Time;
176 std::string Name;
177 std::string Description;
178
179 PrintRecord(const PrintRecord &Other) = default;
180 PrintRecord &operator=(const PrintRecord &Other) = default;
181 PrintRecord(const TimeRecord &Time, const std::string &Name,
182 const std::string &Description)
183 : Time(Time), Name(Name), Description(Description) {}
184
185 bool operator <(const PrintRecord &Other) const {
186 return Time < Other.Time;
187 }
188 };
189 std::string Name;
190 std::string Description;
191 Timer *FirstTimer = nullptr; ///< First timer in the group.
192 std::vector<PrintRecord> TimersToPrint;
193
194 TimerGroup **Prev; ///< Pointer to Next field of previous timergroup in list.
195 TimerGroup *Next; ///< Pointer to next timergroup in list.
196 TimerGroup(const TimerGroup &TG) = delete;
197 void operator=(const TimerGroup &TG) = delete;
198
199public:
200 explicit TimerGroup(StringRef Name, StringRef Description);
201
202 explicit TimerGroup(StringRef Name, StringRef Description,
203 const StringMap<TimeRecord> &Records);
204
205 ~TimerGroup();
206
207 void setName(StringRef NewName, StringRef NewDescription) {
208 Name.assign(first: NewName.begin(), last: NewName.end());
209 Description.assign(first: NewDescription.begin(), last: NewDescription.end());
210 }
211
212 /// Print any started timers in this group, optionally resetting timers after
213 /// printing them.
214 void print(raw_ostream &OS, bool ResetAfterPrint = false);
215
216 /// Clear all timers in this group.
217 void clear();
218
219 /// This static method prints all timers.
220 static void printAll(raw_ostream &OS);
221
222 /// Clear out all timers. This is mostly used to disable automatic
223 /// printing on shutdown, when timers have already been printed explicitly
224 /// using \c printAll or \c printJSONValues.
225 static void clearAll();
226
227 const char *printJSONValues(raw_ostream &OS, const char *delim);
228
229 /// Prints all timers as JSON key/value pairs.
230 static const char *printAllJSONValues(raw_ostream &OS, const char *delim);
231
232 /// Ensure global objects required for statistics printing are initialized.
233 /// This function is used by the Statistic code to ensure correct order of
234 /// global constructors and destructors.
235 static void constructForStatistics();
236
237 /// This makes the default group unmanaged, and lets the user manage the
238 /// group's lifetime.
239 static std::unique_ptr<TimerGroup> aquireDefaultGroup();
240
241private:
242 friend class Timer;
243 friend void PrintStatisticsJSON(raw_ostream &OS);
244 void addTimer(Timer &T);
245 void removeTimer(Timer &T);
246 void prepareToPrintList(bool reset_time = false);
247 void PrintQueuedTimers(raw_ostream &OS);
248 void printJSONValue(raw_ostream &OS, const PrintRecord &R,
249 const char *suffix, double Value);
250};
251
252} // end namespace llvm
253
254#endif
255

source code of llvm/include/llvm/Support/Timer.h