chrome/browser/mac/mac_startup_profiler.h

   1 // Copyright 2014 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_MAC_MAC_STARTUP_PROFILER_H_
   6 #define CHROME_BROWSER_MAC_MAC_STARTUP_PROFILER_H_
   7
   8 #include <map>
   9
  10 #include "base/memory/singleton.h"
  11 #include "base/time/time.h"
  12
  13 // A lightweight profiler of startup performance. Records UMA metrics for the
  14 // time delta between Chrome's launch and major initialization phases.
  15 class MacStartupProfiler {
  16  public:
  17   // Returns pointer to the singleton instance for the current process.
  18   static MacStartupProfiler* GetInstance();
  19
  20   MacStartupProfiler();
  21   ~MacStartupProfiler();
  22
  23   // These locations correspond to major phases of Chrome startup.
  24   // Profiling of these locations should occur at the beginning of the method
  25   // indicated by the enum name.
  26   // The ordering of the enum matches the order in which the initialization
  27   // phases are reached.
  28   enum Location {
  29     PRE_MAIN_MESSAGE_LOOP_START,
  30     AWAKE_FROM_NIB,
  31     POST_MAIN_MESSAGE_LOOP_START,
  32     PRE_PROFILE_INIT,
  33     POST_PROFILE_INIT,
  34     WILL_FINISH_LAUNCHING,
  35     DID_FINISH_LAUNCHING,
  36   };
  37
  38   // Record timestamp for the given location event.
  39   void Profile(Location location);
  40
  41   // Call once to record all UMA metrics for all profiled locations.
  42   void RecordMetrics();
  43
  44  private:
  45   friend struct DefaultSingletonTraits<MacStartupProfiler>;
  46
  47   // Returns the name of the histogram for the given location.
  48   const std::string HistogramName(Location location);
  49
  50   // Records UMA metrics for a specific location.
  51   void RecordHistogram(Location location, const base::TimeDelta& delta);
  52
  53   // Keeps track of the time at which each initialization phase was reached.
  54   std::map<Location, base::Time> profiled_times_;
  55
  56   // Whether UMA metrics have been recorded. Only record UMA metrics once.
  57   bool recorded_metrics_;
  58
  59   DISALLOW_COPY_AND_ASSIGN(MacStartupProfiler);
  60 };
  61
  62 #endif  // CHROME_BROWSER_MAC_MAC_STARTUP_PROFILER_H_