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