1 //===-- llvm/Support/Timer.h - Interval Timing Support ----------*- C++ -*-===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #ifndef LLVM_SUPPORT_TIMER_H
11 #define LLVM_SUPPORT_TIMER_H
12 
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 
20 namespace llvm {
21 
22 class Timer;
23 class TimerGroup;
24 class raw_ostream;
25 
26 class 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 public:
TimeRecord()32   TimeRecord() : WallTime(0), UserTime(0), SystemTime(0), MemUsed(0) {}
33 
34   /// getCurrentTime - Get the current time and memory usage.  If Start is true
35   /// we get the memory usage before the time, otherwise we get time before
36   /// memory usage.  This matters if the time to get the memory usage is
37   /// significant and shouldn't be counted as part of a duration.
38   static TimeRecord getCurrentTime(bool Start = true);
39 
getProcessTime()40   double getProcessTime() const { return UserTime + SystemTime; }
getUserTime()41   double getUserTime() const { return UserTime; }
getSystemTime()42   double getSystemTime() const { return SystemTime; }
getWallTime()43   double getWallTime() const { return WallTime; }
getMemUsed()44   ssize_t getMemUsed() const { return MemUsed; }
45 
46   // operator< - Allow sorting.
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   }
58   void operator-=(const TimeRecord &RHS) {
59     WallTime   -= RHS.WallTime;
60     UserTime   -= RHS.UserTime;
61     SystemTime -= RHS.SystemTime;
62     MemUsed    -= RHS.MemUsed;
63   }
64 
65   /// print - Print the current timer to standard error, and reset the "Started"
66   /// flag.
67   void print(const TimeRecord &Total, raw_ostream &OS) const;
68 };
69 
70 /// Timer - This class is used to track the amount of time spent between
71 /// invocations of its startTimer()/stopTimer() methods.  Given appropriate OS
72 /// support it can also keep track of the RSS of the program at various points.
73 /// By default, the Timer will print the amount of time it has captured to
74 /// standard error when the last timer is destroyed, otherwise it is printed
75 /// when its TimerGroup is destroyed.  Timers do not print their information
76 /// if they are never started.
77 ///
78 class Timer {
79   TimeRecord Time;
80   std::string Name;      // The name of this time variable.
81   bool Started;          // Has this time variable ever been started?
82   TimerGroup *TG;        // The TimerGroup this Timer is in.
83 
84   Timer **Prev, *Next;   // Doubly linked list of timers in the group.
85 public:
Timer(StringRef N)86   explicit Timer(StringRef N) : TG(nullptr) { init(N); }
Timer(StringRef N,TimerGroup & tg)87   Timer(StringRef N, TimerGroup &tg) : TG(nullptr) { init(N, tg); }
Timer(const Timer & RHS)88   Timer(const Timer &RHS) : TG(nullptr) {
89     assert(!RHS.TG && "Can only copy uninitialized timers");
90   }
91   const Timer &operator=(const Timer &T) {
92     assert(!TG && !T.TG && "Can only assign uninit timers");
93     return *this;
94   }
95   ~Timer();
96 
97   // Create an uninitialized timer, client must use 'init'.
Timer()98   explicit Timer() : TG(nullptr) {}
99   void init(StringRef N);
100   void init(StringRef N, TimerGroup &tg);
101 
getName()102   const std::string &getName() const { return Name; }
isInitialized()103   bool isInitialized() const { return TG != nullptr; }
104 
105   /// startTimer - Start the timer running.  Time between calls to
106   /// startTimer/stopTimer is counted by the Timer class.  Note that these calls
107   /// must be correctly paired.
108   ///
109   void startTimer();
110 
111   /// stopTimer - Stop the timer.
112   ///
113   void stopTimer();
114 
115 private:
116   friend class TimerGroup;
117 };
118 
119 /// The TimeRegion class is used as a helper class to call the startTimer() and
120 /// stopTimer() methods of the Timer class.  When the object is constructed, it
121 /// starts the timer specified as its argument.  When it is destroyed, it stops
122 /// the relevant timer.  This makes it easy to time a region of code.
123 ///
124 class TimeRegion {
125   Timer *T;
126   TimeRegion(const TimeRegion &) = delete;
127 
128 public:
TimeRegion(Timer & t)129   explicit TimeRegion(Timer &t) : T(&t) {
130     T->startTimer();
131   }
TimeRegion(Timer * t)132   explicit TimeRegion(Timer *t) : T(t) {
133     if (T) T->startTimer();
134   }
~TimeRegion()135   ~TimeRegion() {
136     if (T) T->stopTimer();
137   }
138 };
139 
140 /// NamedRegionTimer - This class is basically a combination of TimeRegion and
141 /// Timer.  It allows you to declare a new timer, AND specify the region to
142 /// time, all in one statement.  All timers with the same name are merged.  This
143 /// is primarily used for debugging and for hunting performance problems.
144 ///
145 struct NamedRegionTimer : public TimeRegion {
146   explicit NamedRegionTimer(StringRef Name,
147                             bool Enabled = true);
148   explicit NamedRegionTimer(StringRef Name, StringRef GroupName,
149                             bool Enabled = true);
150 };
151 
152 /// The TimerGroup class is used to group together related timers into a single
153 /// report that is printed when the TimerGroup is destroyed.  It is illegal to
154 /// destroy a TimerGroup object before all of the Timers in it are gone.  A
155 /// TimerGroup can be specified for a newly created timer in its constructor.
156 ///
157 class TimerGroup {
158   std::string Name;
159   Timer *FirstTimer;   // First timer in the group.
160   std::vector<std::pair<TimeRecord, std::string>> TimersToPrint;
161 
162   TimerGroup **Prev, *Next; // Doubly linked list of TimerGroup's.
163   TimerGroup(const TimerGroup &TG) = delete;
164   void operator=(const TimerGroup &TG) = delete;
165 
166 public:
167   explicit TimerGroup(StringRef name);
168   ~TimerGroup();
169 
setName(StringRef name)170   void setName(StringRef name) { Name.assign(name.begin(), name.end()); }
171 
172   /// print - Print any started timers in this group and zero them.
173   void print(raw_ostream &OS);
174 
175   /// printAll - This static method prints all timers and clears them all out.
176   static void printAll(raw_ostream &OS);
177 
178 private:
179   friend class Timer;
180   void addTimer(Timer &T);
181   void removeTimer(Timer &T);
182   void PrintQueuedTimers(raw_ostream &OS);
183 };
184 
185 } // End llvm namespace
186 
187 #endif
188