Home | History | Annotate | Download | only in base 
      1 // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef BASE_PERFTIMER_H_
      6 #define BASE_PERFTIMER_H_
      7 #pragma once
      8 
      9 #include <string>
     10 
     11 #include "base/basictypes.h"
     12 #include "base/time.h"
     13 
     14 class FilePath;
     15 
     16 // ----------------------------------------------------------------------
     17 // Initializes and finalizes the perf log. These functions should be
     18 // called at the beginning and end (respectively) of running all the
     19 // performance tests. The init function returns true on success.
     20 // ----------------------------------------------------------------------
     21 bool InitPerfLog(const FilePath& log_path);
     22 void FinalizePerfLog();
     23 
     24 // ----------------------------------------------------------------------
     25 // LogPerfResult
     26 //   Writes to the perf result log the given 'value' resulting from the
     27 //   named 'test'. The units are to aid in reading the log by people.
     28 // ----------------------------------------------------------------------
     29 void LogPerfResult(const char* test_name, double value, const char* units);
     30 
     31 // ----------------------------------------------------------------------
     32 // PerfTimer
     33 //   A simple wrapper around Now()
     34 // ----------------------------------------------------------------------
     35 class PerfTimer {
     36  public:
     37   PerfTimer() {
     38     begin_ = base::TimeTicks::Now();
     39   }
     40 
     41   // Returns the time elapsed since object construction
     42   base::TimeDelta Elapsed() const {
     43     return base::TimeTicks::Now() - begin_;
     44   }
     45 
     46  private:
     47   base::TimeTicks begin_;
     48 };
     49 
     50 // ----------------------------------------------------------------------
     51 // PerfTimeLogger
     52 //   Automates calling LogPerfResult for the common case where you want
     53 //   to measure the time that something took. Call Done() when the test
     54 //   is complete if you do extra work after the test or there are stack
     55 //   objects with potentially expensive constructors. Otherwise, this
     56 //   class with automatically log on destruction.
     57 // ----------------------------------------------------------------------
     58 class PerfTimeLogger {
     59  public:
     60   explicit PerfTimeLogger(const char* test_name)
     61       : logged_(false),
     62         test_name_(test_name) {
     63   }
     64 
     65   ~PerfTimeLogger() {
     66     if (!logged_)
     67       Done();
     68   }
     69 
     70   void Done() {
     71     // we use a floating-point millisecond value because it is more
     72     // intuitive than microseconds and we want more precision than
     73     // integer milliseconds
     74     LogPerfResult(test_name_.c_str(), timer_.Elapsed().InMillisecondsF(), "ms");
     75     logged_ = true;
     76   }
     77 
     78  private:
     79   bool logged_;
     80   std::string test_name_;
     81   PerfTimer timer_;
     82 };
     83 
     84 #endif  // BASE_PERFTIMER_H_
     85