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; ///< Wall clock time elapsed in seconds.
27 double UserTime; ///< User time elapsed.
28 double SystemTime; ///< System time elapsed.
29 ssize_t MemUsed; ///< Memory allocated (in bytes).
30 uint64_t InstructionsExecuted; ///< Number of instructions executed
31public:
32 TimeRecord()
33 : WallTime(0), UserTime(0), SystemTime(0), MemUsed(0),
34 InstructionsExecuted(0) {}
35
36 /// Get the current time and memory usage. If Start is true we get the memory
37 /// usage before the time, otherwise we get time before memory usage. This
38 /// matters if the time to get the memory usage is significant and shouldn't
39 /// be counted as part of a duration.
40 static TimeRecord getCurrentTime(bool Start = true);
41
42 double getProcessTime() const { return UserTime + SystemTime; }
43 double getUserTime() const { return UserTime; }
44 double getSystemTime() const { return SystemTime; }
45 double getWallTime() const { return WallTime; }
46 ssize_t getMemUsed() const { return MemUsed; }
47 uint64_t getInstructionsExecuted() const { return InstructionsExecuted; }
48
49 bool operator<(const TimeRecord &T) const {
50 // Sort by Wall Time elapsed, as it is the only thing really accurate
51 return WallTime < T.WallTime;
52 }
53
54 void operator+=(const TimeRecord &RHS) {
55 WallTime += RHS.WallTime;
56 UserTime += RHS.UserTime;
57 SystemTime += RHS.SystemTime;
58 MemUsed += RHS.MemUsed;
59 InstructionsExecuted += RHS.InstructionsExecuted;
60 }
61 void operator-=(const TimeRecord &RHS) {
62 WallTime -= RHS.WallTime;
63 UserTime -= RHS.UserTime;
64 SystemTime -= RHS.SystemTime;
65 MemUsed -= RHS.MemUsed;
66 InstructionsExecuted -= RHS.InstructionsExecuted;
67 }
68
69 /// Print the current time record to \p OS, with a breakdown showing
70 /// contributions to the \p Total time record.
71 void print(const TimeRecord &Total, raw_ostream &OS) const;
72};
73
74/// This class is used to track the amount of time spent between invocations of
75/// its startTimer()/stopTimer() methods. Given appropriate OS support it can
76/// also keep track of the RSS of the program at various points. By default,
77/// the Timer will print the amount of time it has captured to standard error
78/// when the last timer is destroyed, otherwise it is printed when its
79/// TimerGroup is destroyed. Timers do not print their information if they are
80/// never started.
81class Timer {
82 TimeRecord Time; ///< The total time captured.
83 TimeRecord StartTime; ///< The time startTimer() was last called.
84 std::string Name; ///< The name of this time variable.
85 std::string Description; ///< Description of this time variable.
86 bool Running = false; ///< Is the timer currently running?
87 bool Triggered = false; ///< Has the timer ever been triggered?
88 TimerGroup *TG = nullptr; ///< The TimerGroup this Timer is in.
89
90 Timer **Prev = nullptr; ///< Pointer to \p Next of previous timer in group.
91 Timer *Next = nullptr; ///< Next timer in the group.
92public:
93 explicit Timer(StringRef TimerName, StringRef TimerDescription) {
94 init(TimerName, TimerDescription);
95 }
96 Timer(StringRef TimerName, StringRef TimerDescription, TimerGroup &tg) {
97 init(TimerName, TimerDescription, tg);
98 }
99 Timer(const Timer &RHS) {
100 assert(!RHS.TG && "Can only copy uninitialized timers");
101 }
102 const Timer &operator=(const Timer &T) {
103 assert(!TG && !T.TG && "Can only assign uninit timers");
104 return *this;
105 }
106 ~Timer();
107
108 /// Create an uninitialized timer, client must use 'init'.
109 explicit Timer() = default;
110 void init(StringRef TimerName, StringRef TimerDescription);
111 void init(StringRef TimerName, StringRef TimerDescription, TimerGroup &tg);
112
113 const std::string &getName() const { return Name; }
114 const std::string &getDescription() const { return Description; }
115 bool isInitialized() const { return TG != nullptr; }
116
117 /// Check if the timer is currently running.
118 bool isRunning() const { return Running; }
119
120 /// Check if startTimer() has ever been called on this timer.
121 bool hasTriggered() const { return Triggered; }
122
123 /// Start the timer running. Time between calls to startTimer/stopTimer is
124 /// counted by the Timer class. Note that these calls must be correctly
125 /// paired.
126 void startTimer();
127
128 /// Stop the timer.
129 void stopTimer();
130
131 /// Clear the timer state.
132 void clear();
133
134 /// Return the duration for which this timer has been running.
135 TimeRecord getTotalTime() const { return Time; }
136
137private:
138 friend class TimerGroup;
139};
140
141/// The TimeRegion class is used as a helper class to call the startTimer() and
142/// stopTimer() methods of the Timer class. When the object is constructed, it
143/// starts the timer specified as its argument. When it is destroyed, it stops
144/// the relevant timer. This makes it easy to time a region of code.
145class TimeRegion {
146 Timer *T;
147 TimeRegion(const TimeRegion &) = delete;
148
149public:
150 explicit TimeRegion(Timer &t) : T(&t) {
151 T->startTimer();
152 }
153 explicit TimeRegion(Timer *t) : T(t) {
154 if (T) T->startTimer();
155 }
156 ~TimeRegion() {
157 if (T) T->stopTimer();
158 }
159};
160
161/// This class is basically a combination of TimeRegion and Timer. It allows
162/// you to declare a new timer, AND specify the region to time, all in one
163/// statement. All timers with the same name are merged. This is primarily
164/// used for debugging and for hunting performance problems.
165struct NamedRegionTimer : public TimeRegion {
166 explicit NamedRegionTimer(StringRef Name, StringRef Description,
167 StringRef GroupName,
168 StringRef GroupDescription, bool Enabled = true);
169};
170
171/// The TimerGroup class is used to group together related timers into a single
172/// report that is printed when the TimerGroup is destroyed. It is illegal to
173/// destroy a TimerGroup object before all of the Timers in it are gone. A
174/// TimerGroup can be specified for a newly created timer in its constructor.
175class TimerGroup {
176 struct PrintRecord {
177 TimeRecord Time;
178 std::string Name;
179 std::string Description;
180
181 PrintRecord(const PrintRecord &Other) = default;
182 PrintRecord &operator=(const PrintRecord &Other) = default;
183 PrintRecord(const TimeRecord &Time, const std::string &Name,
184 const std::string &Description)
185 : Time(Time), Name(Name), Description(Description) {}
186
187 bool operator <(const PrintRecord &Other) const {
188 return Time < Other.Time;
189 }
190 };
191 std::string Name;
192 std::string Description;
193 Timer *FirstTimer = nullptr; ///< First timer in the group.
194 std::vector<PrintRecord> TimersToPrint;
195
196 TimerGroup **Prev; ///< Pointer to Next field of previous timergroup in list.
197 TimerGroup *Next; ///< Pointer to next timergroup in list.
198 TimerGroup(const TimerGroup &TG) = delete;
199 void operator=(const TimerGroup &TG) = delete;
200
201public:
202 explicit TimerGroup(StringRef Name, StringRef Description);
203
204 explicit TimerGroup(StringRef Name, StringRef Description,
205 const StringMap<TimeRecord> &Records);
206
207 ~TimerGroup();
208
209 void setName(StringRef NewName, StringRef NewDescription) {
210 Name.assign(NewName.begin(), NewName.end());
211 Description.assign(NewDescription.begin(), NewDescription.end());
212 }
213
214 /// Print any started timers in this group, optionally resetting timers after
215 /// printing them.
216 void print(raw_ostream &OS, bool ResetAfterPrint = false);
217
218 /// Clear all timers in this group.
219 void clear();
220
221 /// This static method prints all timers.
222 static void printAll(raw_ostream &OS);
223
224 /// Clear out all timers. This is mostly used to disable automatic
225 /// printing on shutdown, when timers have already been printed explicitly
226 /// using \c printAll or \c printJSONValues.
227 static void clearAll();
228
229 const char *printJSONValues(raw_ostream &OS, const char *delim);
230
231 /// Prints all timers as JSON key/value pairs.
232 static const char *printAllJSONValues(raw_ostream &OS, const char *delim);
233
234 /// Ensure global timer group lists are initialized. This function is mostly
235 /// used by the Statistic code to influence the construction and destruction
236 /// order of the global timer lists.
237 static void ConstructTimerLists();
238
239 /// This makes the default group unmanaged, and lets the user manage the
240 /// group's lifetime.
241 static std::unique_ptr<TimerGroup> aquireDefaultGroup();
242
243private:
244 friend class Timer;
245 friend void PrintStatisticsJSON(raw_ostream &OS);
246 void addTimer(Timer &T);
247 void removeTimer(Timer &T);
248 void prepareToPrintList(bool reset_time = false);
249 void PrintQueuedTimers(raw_ostream &OS);
250 void printJSONValue(raw_ostream &OS, const PrintRecord &R,
251 const char *suffix, double Value);
252};
253
254} // end namespace llvm
255
256#endif
257

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