base/debug/trace_event_system_stats_monitor.h

   1 // Copyright 2013 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_DEBUG_TRACE_EVENT_SYSTEM_STATS_MONITOR_H_
   6 #define BASE_DEBUG_TRACE_EVENT_SYSTEM_STATS_MONITOR_H_
   7
   8 #include "base/base_export.h"
   9 #include "base/debug/trace_event_impl.h"
  10 #include "base/gtest_prod_util.h"
  11 #include "base/memory/ref_counted.h"
  12 #include "base/memory/weak_ptr.h"
  13 #include "base/process/process_metrics.h"
  14 #include "base/timer/timer.h"
  15
  16 namespace base {
  17
  18 class SingleThreadTaskRunner;
  19
  20 namespace debug {
  21
  22 // Watches for chrome://tracing to be enabled or disabled. When tracing is
  23 // enabled, also enables system events profiling. This class is the preferred
  24 // way to turn system tracing on and off.
  25 class BASE_EXPORT TraceEventSystemStatsMonitor
  26     : public TraceLog::EnabledStateObserver {
  27  public:
  28   // Length of time interval between stat profiles.
  29   static const int kSamplingIntervalMilliseconds = 2000;
  30
  31   // |task_runner| must be the primary thread for the client
  32   // process, e.g. the UI thread in a browser.
  33   explicit TraceEventSystemStatsMonitor(
  34       scoped_refptr<SingleThreadTaskRunner> task_runner);
  35
  36   virtual ~TraceEventSystemStatsMonitor();
  37
  38   // base::debug::TraceLog::EnabledStateChangedObserver overrides:
  39   virtual void OnTraceLogEnabled() OVERRIDE;
  40   virtual void OnTraceLogDisabled() OVERRIDE;
  41
  42   // Retrieves system profiling at the current time.
  43   void DumpSystemStats();
  44
  45  private:
  46   FRIEND_TEST_ALL_PREFIXES(TraceSystemStatsMonitorTest,
  47                            TraceEventSystemStatsMonitor);
  48
  49   bool IsTimerRunningForTest() const;
  50
  51   void StartProfiling();
  52
  53   void StopProfiling();
  54
  55   // Ensures the observer starts and stops tracing on the primary thread.
  56   scoped_refptr<SingleThreadTaskRunner> task_runner_;
  57
  58   // Timer to schedule system profile dumps.
  59   RepeatingTimer<TraceEventSystemStatsMonitor> dump_timer_;
  60
  61   WeakPtrFactory<TraceEventSystemStatsMonitor> weak_factory_;
  62
  63   DISALLOW_COPY_AND_ASSIGN(TraceEventSystemStatsMonitor);
  64 };
  65
  66 // Converts system memory profiling stats in |input| to
  67 // trace event compatible JSON and appends to |output|. Visible for testing.
  68 BASE_EXPORT void AppendSystemProfileAsTraceFormat(const SystemMetrics&
  69                                                   system_stats,
  70                                                   std::string* output);
  71
  72 }  // namespace debug
  73 }  // namespace base
  74
  75 #endif  // BASE_DEBUG_TRACE_EVENT_SYSTEM_STATS_MONITOR_H_