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 <string>
17#include <utility>
18#include <vector>
19
20namespace llvm {
21
22class Timer;
23class TimerGroup;
24class raw_ostream;
25
26class TimeRecord {
27 double WallTime; ///< Wall clock time elapsed in seconds.
28 double UserTime; ///< User time elapsed.
29 double SystemTime; ///< System time elapsed.
30 ssize_t MemUsed; ///< Memory allocated (in bytes).
31 uint64_t InstructionsExecuted; ///< Number of instructions executed
32public:
33 TimeRecord()
34 : WallTime(0), UserTime(0), SystemTime(0), MemUsed(0),
35 InstructionsExecuted(0) {}
36
37 /// Get the current time and memory usage. If Start is true we get the memory
38 /// usage before the time, otherwise we get time before memory usage. This
39 /// matters if the time to get the memory usage is significant and shouldn't
40 /// be counted as part of a duration.
41 static TimeRecord getCurrentTime(bool Start = true);
42
43 double getProcessTime() const { return UserTime + SystemTime; }
44 double getUserTime() const { return UserTime; }
45 double getSystemTime() const { return SystemTime; }
46 double getWallTime() const { return WallTime; }
47 ssize_t getMemUsed() const { return MemUsed; }
48 uint64_t getInstructionsExecuted() const { return InstructionsExecuted; }
49
50 bool operator<(const TimeRecord &T) const {
51 // Sort by Wall Time elapsed, as it is the only thing really accurate
52 return WallTime < T.WallTime;
53 }
54
55 void operator+=(const TimeRecord &RHS) {
56 WallTime += RHS.WallTime;
57 UserTime += RHS.UserTime;
58 SystemTime += RHS.SystemTime;
59 MemUsed += RHS.MemUsed;
60 InstructionsExecuted += RHS.InstructionsExecuted;
61 }
62 void operator-=(const TimeRecord &RHS) {
63 WallTime -= RHS.WallTime;
64 UserTime -= RHS.UserTime;
65 SystemTime -= RHS.SystemTime;
66 MemUsed -= RHS.MemUsed;
67 InstructionsExecuted -= RHS.InstructionsExecuted;
68 }
69
70 /// Print the current time record to \p OS, with a breakdown showing
71 /// contributions to the \p Total time record.
72 void print(const TimeRecord &Total, raw_ostream &OS) const;
73};
74
75/// This class is used to track the amount of time spent between invocations of
76/// its startTimer()/stopTimer() methods. Given appropriate OS support it can
77/// also keep track of the RSS of the program at various points. By default,
78/// the Timer will print the amount of time it has captured to standard error
79/// when the last timer is destroyed, otherwise it is printed when its
80/// TimerGroup is destroyed. Timers do not print their information if they are
81/// never started.
82class Timer {
83 TimeRecord Time; ///< The total time captured.
84 TimeRecord StartTime; ///< The time startTimer() was last called.
85 std::string Name; ///< The name of this time variable.
86 std::string Description; ///< Description of this time variable.
87 bool Running = false; ///< Is the timer currently running?
88 bool Triggered = false; ///< Has the timer ever been triggered?
89 TimerGroup *TG = nullptr; ///< The TimerGroup this Timer is in.
90
91 Timer **Prev = nullptr; ///< Pointer to \p Next of previous timer in group.
92 Timer *Next = nullptr; ///< Next timer in the group.
93public:
94 explicit Timer(StringRef TimerName, StringRef TimerDescription) {
95 init(TimerName, TimerDescription);
96 }
97 Timer(StringRef TimerName, StringRef TimerDescription, TimerGroup &tg) {
98 init(TimerName, TimerDescription, tg);
99 }
100 Timer(const Timer &RHS) {
101 assert(!RHS.TG && "Can only copy uninitialized timers");
102 }
103 const Timer &operator=(const Timer &T) {
104 assert(!TG && !T.TG && "Can only assign uninit timers");
105 return *this;
106 }
107 ~Timer();
108
109 /// Create an uninitialized timer, client must use 'init'.
110 explicit Timer() {}
111 void init(StringRef TimerName, StringRef TimerDescription);
112 void init(StringRef TimerName, StringRef TimerDescription, TimerGroup &tg);
113
114 const std::string &getName() const { return Name; }
115 const std::string &getDescription() const { return Description; }
116 bool isInitialized() const { return TG != nullptr; }
117
118 /// Check if the timer is currently running.
119 bool isRunning() const { return Running; }
120
121 /// Check if startTimer() has ever been called on this timer.
122 bool hasTriggered() const { return Triggered; }
123
124 /// Start the timer running. Time between calls to startTimer/stopTimer is
125 /// counted by the Timer class. Note that these calls must be correctly
126 /// paired.
127 void startTimer();
128
129 /// Stop the timer.
130 void stopTimer();
131
132 /// Clear the timer state.
133 void clear();
134
135 /// Return the duration for which this timer has been running.
136 TimeRecord getTotalTime() const { return Time; }
137
138private:
139 friend class TimerGroup;
140};
141
142/// The TimeRegion class is used as a helper class to call the startTimer() and
143/// stopTimer() methods of the Timer class. When the object is constructed, it
144/// starts the timer specified as its argument. When it is destroyed, it stops
145/// the relevant timer. This makes it easy to time a region of code.
146class TimeRegion {
147 Timer *T;
148 TimeRegion(const TimeRegion &) = delete;
149
150public:
151 explicit TimeRegion(Timer &t) : T(&t) {
152 T->startTimer();
153 }
154 explicit TimeRegion(Timer *t) : T(t) {
155 if (T) T->startTimer();
156 }
157 ~TimeRegion() {
158 if (T) T->stopTimer();
159 }
160};
161
162/// This class is basically a combination of TimeRegion and Timer. It allows
163/// you to declare a new timer, AND specify the region to time, all in one
164/// statement. All timers with the same name are merged. This is primarily
165/// used for debugging and for hunting performance problems.
166struct NamedRegionTimer : public TimeRegion {
167 explicit NamedRegionTimer(StringRef Name, StringRef Description,
168 StringRef GroupName,
169 StringRef GroupDescription, bool Enabled = true);
170};
171
172/// The TimerGroup class is used to group together related timers into a single
173/// report that is printed when the TimerGroup is destroyed. It is illegal to
174/// destroy a TimerGroup object before all of the Timers in it are gone. A
175/// TimerGroup can be specified for a newly created timer in its constructor.
176class TimerGroup {
177 struct PrintRecord {
178 TimeRecord Time;
179 std::string Name;
180 std::string Description;
181
182 PrintRecord(const PrintRecord &Other) = default;
183 PrintRecord &operator=(const PrintRecord &Other) = default;
184 PrintRecord(const TimeRecord &Time, const std::string &Name,
185 const std::string &Description)
186 : Time(Time), Name(Name), Description(Description) {}
187
188 bool operator <(const PrintRecord &Other) const {
189 return Time < Other.Time;
190 }
191 };
192 std::string Name;
193 std::string Description;
194 Timer *FirstTimer = nullptr; ///< First timer in the group.
195 std::vector<PrintRecord> TimersToPrint;
196
197 TimerGroup **Prev; ///< Pointer to Next field of previous timergroup in list.
198 TimerGroup *Next; ///< Pointer to next timergroup in list.
199 TimerGroup(const TimerGroup &TG) = delete;
200 void operator=(const TimerGroup &TG) = delete;
201
202public:
203 explicit TimerGroup(StringRef Name, StringRef Description);
204
205 explicit TimerGroup(StringRef Name, StringRef Description,
206 const StringMap<TimeRecord> &Records);
207
208 ~TimerGroup();
209
210 void setName(StringRef NewName, StringRef NewDescription) {
211 Name.assign(NewName.begin(), NewName.end());
212 Description.assign(NewDescription.begin(), NewDescription.end());
213 }
214
215 /// Print any started timers in this group, optionally resetting timers after
216 /// printing them.
217 void print(raw_ostream &OS, bool ResetAfterPrint = false);
218
219 /// Clear all timers in this group.
220 void clear();
221
222 /// This static method prints all timers.
223 static void printAll(raw_ostream &OS);
224
225 /// Clear out all timers. This is mostly used to disable automatic
226 /// printing on shutdown, when timers have already been printed explicitly
227 /// using \c printAll or \c printJSONValues.
228 static void clearAll();
229
230 const char *printJSONValues(raw_ostream &OS, const char *delim);
231
232 /// Prints all timers as JSON key/value pairs.
233 static const char *printAllJSONValues(raw_ostream &OS, const char *delim);
234
235 /// Ensure global timer group lists are initialized. This function is mostly
236 /// used by the Statistic code to influence the construction and destruction
237 /// order of the global timer lists.
238 static void ConstructTimerLists();
239
240 /// This makes the default group unmanaged, and lets the user manage the
241 /// group's lifetime.
242 static std::unique_ptr<TimerGroup> aquireDefaultGroup();
243
244private:
245 friend class Timer;
246 friend void PrintStatisticsJSON(raw_ostream &OS);
247 void addTimer(Timer &T);
248 void removeTimer(Timer &T);
249 void prepareToPrintList(bool reset_time = false);
250 void PrintQueuedTimers(raw_ostream &OS);
251 void printJSONValue(raw_ostream &OS, const PrintRecord &R,
252 const char *suffix, double Value);
253};
254
255} // end namespace llvm
256
257#endif
258