COIN-OR::LEMON - Graph Library

source: lemon-0.x/lemon/time_measure.h @ 1811:597ce92fae73

Last change on this file since 1811:597ce92fae73 was 1811:597ce92fae73, checked in by Alpar Juttner, 14 years ago

Several bugfices.

File size: 10.0 KB
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1/* -*- C++ -*-
2 * lemon/time_measure.h - Part of LEMON, a generic C++ optimization library
3 *
4 * Copyright (C) 2005 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
5 * (Egervary Research Group on Combinatorial Optimization, EGRES).
6 *
7 * Permission to use, modify and distribute this software is granted
8 * provided that this copyright notice appears in all copies. For
9 * precise terms see the accompanying LICENSE file.
10 *
11 * This software is provided "AS IS" with no warranty of any kind,
12 * express or implied, and with no claim as to its suitability for any
13 * purpose.
14 *
15 */
16
17#ifndef LEMON_TIME_MEASURE_H
18#define LEMON_TIME_MEASURE_H
19
20///\ingroup misc
21///\file
22///\brief Tools for measuring cpu usage
23
24#include <sys/time.h>
25#include <sys/times.h>
26#include <fstream>
27#include <iostream>
28#include <unistd.h>
29
30namespace lemon {
31
32  /// \addtogroup misc
33  /// @{
34
35  /// A class to store (cpu)time instances.
36
37  /// This class stores five time values.
38  /// - a real time
39  /// - a user cpu time
40  /// - a system cpu time
41  /// - a user cpu time of children
42  /// - a system cpu time of children
43  ///
44  /// TimeStamp's can be added to or substracted from each other and
45  /// they can be pushed to a stream.
46  ///
47  /// In most cases, perhaps \ref Timer class is what you want to use instead.
48  ///
49  ///\author Alpar Juttner
50
51  class TimeStamp
52  {
53    struct rtms
54    {
55      double tms_utime;
56      double tms_stime;
57      double tms_cutime;
58      double tms_cstime;
59      rtms() {}
60      rtms(tms ts) : tms_utime(ts.tms_utime), tms_stime(ts.tms_stime),
61                     tms_cutime(ts.tms_cutime), tms_cstime(ts.tms_cstime) {}
62    };
63    rtms ts;
64    double real_time;
65 
66    rtms &getTms() {return ts;}
67    const rtms &getTms() const {return ts;}
68
69    void _reset()
70    { ts.tms_utime=ts.tms_stime=ts.tms_cutime=ts.tms_cstime=0; real_time=0;}
71
72  public:
73
74    ///Read the current time values of the process
75    void stamp()
76    {
77      timeval tv;
78      tms _ts;
79      times(&_ts);
80      gettimeofday(&tv, 0);real_time=tv.tv_sec+double(tv.tv_usec)/1e6;
81      ts=_ts;
82    }
83 
84    /// Constructor initializing with zero
85    TimeStamp()
86    { _reset(); }
87    ///Constructor initializing with the current time values of the process
88    TimeStamp(void *) { stamp();}
89 
90    ///Set every time value to zero
91    TimeStamp &reset() {_reset();return *this;}
92
93    ///\e
94    TimeStamp &operator+=(const TimeStamp &b)
95    {
96      ts.tms_utime+=b.ts.tms_utime;
97      ts.tms_stime+=b.ts.tms_stime;
98      ts.tms_cutime+=b.ts.tms_cutime;
99      ts.tms_cstime+=b.ts.tms_cstime;
100      real_time+=b.real_time;
101      return *this;
102    }
103    ///\e
104    TimeStamp operator+(const TimeStamp &b) const
105    {
106      TimeStamp t(*this);
107      return t+=b;
108    }
109    ///\e
110    TimeStamp &operator-=(const TimeStamp &b)
111    {
112      ts.tms_utime-=b.ts.tms_utime;
113      ts.tms_stime-=b.ts.tms_stime;
114      ts.tms_cutime-=b.ts.tms_cutime;
115      ts.tms_cstime-=b.ts.tms_cstime;
116      real_time-=b.real_time;
117      return *this;
118    }
119    ///\e
120    TimeStamp operator-(const TimeStamp &b) const
121    {
122      TimeStamp t(*this);
123      return t-=b;
124    }
125    ///\e
126    TimeStamp &operator*=(double b)
127    {
128      ts.tms_utime*=b;
129      ts.tms_stime*=b;
130      ts.tms_cutime*=b;
131      ts.tms_cstime*=b;
132      real_time*=b;
133      return *this;
134    }
135    ///\e
136    TimeStamp operator*(double b) const
137    {
138      TimeStamp t(*this);
139      return t*=b;
140    }
141    friend TimeStamp operator*(double b,const TimeStamp &t);
142    ///\e
143    TimeStamp &operator/=(double b)
144    {
145      ts.tms_utime/=b;
146      ts.tms_stime/=b;
147      ts.tms_cutime/=b;
148      ts.tms_cstime/=b;
149      real_time/=b;
150      return *this;
151    }
152    ///\e
153    TimeStamp operator/(double b) const
154    {
155      TimeStamp t(*this);
156      return t/=b;
157    }
158    ///The time ellapsed since the last call of stamp()
159    TimeStamp ellapsed() const
160    {
161      TimeStamp t(NULL);
162      return t-*this;
163    }
164 
165    friend std::ostream& operator<<(std::ostream& os,const TimeStamp &t);
166 
167    ///Gives back the user time of the process
168    double userTime() const
169    {
170      return double(ts.tms_utime)/sysconf(_SC_CLK_TCK);
171    }
172    ///Gives back the system time of the process
173    double systemTime() const
174    {
175      return double(ts.tms_stime)/sysconf(_SC_CLK_TCK);
176    }
177    ///Gives back the user time of the process' children
178    double cUserTime() const
179    {
180      return double(ts.tms_cutime)/sysconf(_SC_CLK_TCK);
181    }
182    ///Gives back the user time of the process' children
183    double cSystemTime() const
184    {
185      return double(ts.tms_cstime)/sysconf(_SC_CLK_TCK);
186    }
187    ///Gives back the real time
188    double realTime() const {return real_time;}
189  };
190
191  TimeStamp operator*(double b,const TimeStamp &t)
192  {
193    return t*b;
194  }
195 
196  ///Class for measuring the cpu time and real time usage of the process
197
198  ///Class for measuring the cpu time and real time usage of the process.
199  ///It is quite easy-to-use, here is a short example.
200  ///\code
201  ///#include<lemon/time_measure.h>
202  ///#include<iostream>
203  ///
204  ///int main()
205  ///{
206  ///
207  ///  ...
208  ///
209  ///  Timer T;
210  ///  doSomething();
211  ///  std::cout << T << '\n';
212  ///  T.reset();
213  ///  doSomethingElse();
214  ///  std::cout << T << '\n';
215  ///
216  ///  ...
217  ///
218  ///}
219  ///\endcode
220  ///
221  ///The \ref Timer can also be \ref stop() "stopped" and
222  ///\ref start() "started" again, so it is possible to compute collected
223  ///running times.
224  ///
225  ///\warning Depending on the operation system and its actual configuration
226  ///the time counters have a certain (relatively big) granularity.
227  ///Therefore this tool is not appropriate to measure very short times.
228  ///Also, if you start and stop the timer very frequently, it could lead
229  ///distorted results.
230  ///
231  ///The \ref Timer also counts the number of \ref start()
232  ///executions, and is stops only after the same amount (or more)
233  ///\ref stop() "stop()"s. This can be useful e.g. to compute the running time
234  ///of recursive functions.
235  ///
236  ///\todo This shouldn't be Unix (Linux) specific.
237  ///
238  ///\author Alpar Juttner
239  class Timer
240  {
241    int running; //Timer is running iff running>0; (running>=0 always holds)
242    TimeStamp start_time; //This is the relativ start-time if the timer
243                          //is running, the collected running time otherwise.
244   
245    void _reset() {if(running) start_time.stamp(); else start_time.reset();}
246 
247  public:
248    ///Constructor.
249
250    ///\param _running indicates whether or not the timer starts immediately.
251    ///
252    Timer(bool _running=true) :running(_running) {_reset();}
253
254    ///Computes the ellapsed time
255
256    ///This conversion computes the ellapsed time
257    ///
258    operator TimeStamp () const
259    {
260      TimeStamp t;
261      t.stamp();
262      return running?t-start_time:start_time;
263    }
264
265    ///Resets the time counters
266
267    ///Resets the time counters
268    ///
269    void reset()
270    {
271      _reset();
272    }
273
274    ///Start the time counters
275   
276    ///This function starts the time counters.
277    ///
278    ///If the timer is started more than ones, it will remain running
279    ///until the same amount of \ref stop() is called.
280    ///\sa stop()
281    void start()
282    {
283      if(running) running++;
284      else {
285        TimeStamp t;
286        t.stamp();
287        start_time=t-start_time;
288      }
289    }
290   
291    ///Stop the time counters
292
293    ///This function stops the time counters.
294    ///
295    ///\sa stop()
296    void stop()
297    {
298      if(running && !--running) {
299        TimeStamp t;
300        t.stamp();
301        start_time=t-start_time;
302      }
303    }
304   
305    ///Gives back the ellapsed user time of the process
306    double userTime() const
307    {
308      return operator TimeStamp().userTime();
309    }
310    ///Gives back the ellapsed system time of the process
311    double systemTime() const
312    {
313      return operator TimeStamp().systemTime();
314    }
315    ///Gives back the ellapsed user time of the process' children
316    double cUserTime() const
317    {
318      return operator TimeStamp().cUserTime();
319    }
320    ///Gives back the ellapsed user time of the process' children
321    double cSystemTime() const
322    {
323      return operator TimeStamp().cSystemTime();
324    }
325    ///Gives back the ellapsed real time
326    double realTime() const
327    {
328      return operator TimeStamp().realTime();
329    }
330
331  };
332
333  ///Prints the time counters
334
335  ///Prints the time counters in the following form:
336  ///
337  /// <tt>u: XX.XXs s: XX.XXs cu: XX.XXs cs: XX.XXs real: XX.XXs</tt>
338  ///
339  /// where the values are the
340  /// \li \c u: user cpu time,
341  /// \li \c s: system cpu time,
342  /// \li \c cu: user cpu time of children,
343  /// \li \c cs: system cpu time of children,
344  /// \li \c real: real time.
345  /// \relates TimeStamp
346  inline std::ostream& operator<<(std::ostream& os,const TimeStamp &t)
347  {
348    long cls = sysconf(_SC_CLK_TCK);
349    os << "u: " << double(t.getTms().tms_utime)/cls <<
350      "s, s: " << double(t.getTms().tms_stime)/cls <<
351      "s, cu: " << double(t.getTms().tms_cutime)/cls <<
352      "s, cs: " << double(t.getTms().tms_cstime)/cls <<
353      "s, real: " << t.realTime() << "s";
354    return os;
355  }
356
357 
358  ///Tool to measure the running time more exactly.
359 
360  ///This function calls \c f several times and returns the average
361  ///running time. The number of the executions will be choosen in such a way
362  ///that the full real running time will be roughly between \c min_time
363  ///and <tt>2*min_time</tt>.
364  ///\param f the function object to be measured.
365  ///\param min_time the minimum total running time.
366  ///\retval num if it is not \c NULL, then *num will contain the actual
367  ///        number of execution of \c f.
368  ///\retval full_time if it is not \c NULL, then *full_time
369  ///        will contain the actual
370  ///        total running time.
371  ///\return The average running time of \c f.
372 
373  template<class F>
374  TimeStamp runningTimeTest(const F &f,double min_time=10,int *num = NULL,
375                        TimeStamp *full_time=NULL)
376  {
377    Timer t;
378    TimeStamp full;
379    int total=0;
380    for(int tn=1;tn < 1<<24; tn*=2) {
381      for(;total<tn;total++) f();
382      full=t;
383      if(full.realTime()>min_time) {
384        if(num) *num=total;
385        if(full_time) *full_time=full;
386      return full/total;
387      }
388    }
389    return TimeStamp();
390  }
391 
392  /// @} 
393
394
395} //namespace lemon
396
397#endif //LEMON_TIME_MEASURE_H
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