chrome/browser/performance_monitor/startup_timer.h

   1 // Copyright (c) 2012 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 CHROME_BROWSER_PERFORMANCE_MONITOR_STARTUP_TIMER_H_
   6 #define CHROME_BROWSER_PERFORMANCE_MONITOR_STARTUP_TIMER_H_
   7
   8 #include "base/time/time.h"
   9 #include "content/public/browser/notification_observer.h"
  10 #include "content/public/browser/notification_registrar.h"
  11
  12 namespace performance_monitor {
  13
  14 // This class is responsible for recording the startup and session restore times
  15 // (if applicable) for PerformanceMonitor. This allows us to initialize this
  16 // relatively small object early in the startup process, and start the whole of
  17 // PerformanceMonitor at a later time. StartupTimer will record the times and
  18 // insert them into PerformanceMonitor's database.
  19 class StartupTimer : public content::NotificationObserver {
  20  public:
  21   // Indicates the type of startup; i.e. either a normal startup or a testing
  22   // environment.
  23   enum StartupType {
  24     STARTUP_NORMAL,
  25     STARTUP_TEST
  26   };
  27
  28   StartupTimer();
  29   virtual ~StartupTimer();
  30
  31   // Inform StartupTimer that the startup process has been completed; stop the
  32   // timer. Returns false if the timer has already stopped.
  33   bool SignalStartupComplete(StartupType startup_type);
  34
  35   // Pauses the timer until UnpauseTimer() is called; any time spent within a
  36   // pause does not count towards the measured startup time. This will DCHECK if
  37   // PauseTimer() is called while paused or UnpauseTimer() is called while
  38   // unpaused.
  39   static void PauseTimer();
  40   static void UnpauseTimer();
  41
  42   // content::NotificationObserver
  43   // We keep track of whether or not PerformanceMonitor has been started via
  44   // the PERFORMANCE_MONITOR_INITIALIZED notification; we need to know this so
  45   // we know when to insert startup data into the database. We either insert
  46   // data as we gather it (if PerformanceMonitor is started prior to data
  47   // collection) or at the notification (if PerformanceMonitor is started
  48   // later).
  49   virtual void Observe(int type,
  50                        const content::NotificationSource& source,
  51                        const content::NotificationDetails& details) OVERRIDE;
  52
  53   static void SetElapsedSessionRestoreTime(
  54       const base::TimeDelta& elapsed_session_restore_time);
  55
  56  private:
  57   // Insert the elapsed time measures into PerformanceMonitor's database.
  58   void InsertElapsedStartupTime();
  59   void InsertElapsedSessionRestoreTime();
  60
  61   // The time at which the startup process begins (the creation of
  62   // ChromeBrowserMain).
  63   base::TimeTicks startup_begin_;
  64
  65   // The time at which the timer was most recently paused, or null if the timer
  66   // is not currently paused.
  67   base::TimeTicks pause_started_;
  68
  69   // The total duration for which the timer has been paused.
  70   base::TimeDelta total_pause_;
  71
  72   // A flag of whether or not this was a "normal" startup (e.g. whether or not
  73   // this was in a testing environment, which would change the startup time
  74   // values). If it is not a normal startup, we use a different metric.
  75   StartupType startup_type_;
  76
  77   // The total duration of the startup process, minus any pauses.
  78   base::TimeDelta elapsed_startup_time_;
  79
  80   // The total duration of the session restore(s), if any occurred. This is
  81   // independent of the startup time, because:
  82   // - If the user has auto-restore on, the restore is synchronous, and we pause
  83   //   the startup timer during the session restore; the restore will not
  84   //   interfere with startup timing.
  85   // - If Chrome crashed and the user chooses to restore the crashed session,
  86   //   then the startup is already completed; the restore will not interfere
  87   //   with startup timing.
  88   std::vector<base::TimeDelta> elapsed_session_restore_times_;
  89
  90   // Flag whether or not PerformanceMonitor has been fully started.
  91   bool performance_monitor_initialized_;
  92
  93   content::NotificationRegistrar registrar_;
  94
  95   // The singleton of this class.
  96   static StartupTimer* g_startup_timer_;
  97
  98   DISALLOW_COPY_AND_ASSIGN(StartupTimer);
  99 };
 100
 101 }  // namespace performance_monitor
 102
 103 #endif  // CHROME_BROWSER_PERFORMANCE_MONITOR_STARTUP_TIMER_H_