base/debug/trace_event_system_stats_monitor.cc

   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 #include "base/debug/trace_event_system_stats_monitor.h"
   6
   7 #include "base/debug/leak_annotations.h"
   8 #include "base/debug/trace_event.h"
   9 #include "base/json/json_writer.h"
  10 #include "base/lazy_instance.h"
  11 #include "base/logging.h"
  12 #include "base/memory/scoped_ptr.h"
  13 #include "base/strings/string_number_conversions.h"
  14 #include "base/strings/string_util.h"
  15 #include "base/thread_task_runner_handle.h"
  16 #include "base/threading/thread_local_storage.h"
  17
  18 namespace base {
  19 namespace debug {
  20
  21 namespace {
  22
  23 /////////////////////////////////////////////////////////////////////////////
  24 // Holds profiled system stats until the tracing system needs to serialize it.
  25 class SystemStatsHolder : public base::debug::ConvertableToTraceFormat {
  26  public:
  27   SystemStatsHolder() { }
  28   virtual ~SystemStatsHolder() { }
  29
  30   // Fills system_metrics_ with profiled system memory and disk stats.
  31   // Uses the previous stats to compute rates if this is not the first profile.
  32   void GetSystemProfilingStats();
  33
  34   // base::debug::ConvertableToTraceFormat overrides:
  35   virtual void AppendAsTraceFormat(std::string* out) const OVERRIDE {
  36     AppendSystemProfileAsTraceFormat(system_stats_, out);
  37   }
  38
  39  private:
  40   SystemMetrics system_stats_;
  41
  42   DISALLOW_COPY_AND_ASSIGN(SystemStatsHolder);
  43 };
  44
  45 void SystemStatsHolder::GetSystemProfilingStats() {
  46   system_stats_ = SystemMetrics::Sample();
  47 }
  48
  49 }  // namespace
  50
  51 //////////////////////////////////////////////////////////////////////////////
  52
  53 TraceEventSystemStatsMonitor::TraceEventSystemStatsMonitor(
  54     scoped_refptr<SingleThreadTaskRunner> task_runner)
  55     : task_runner_(task_runner),
  56       weak_factory_(this) {
  57   // Force the "system_stats" category to show up in the trace viewer.
  58   TraceLog::GetCategoryGroupEnabled(TRACE_DISABLED_BY_DEFAULT("system_stats"));
  59
  60   // Allow this to be instantiated on unsupported platforms, but don't run.
  61   TraceLog::GetInstance()->AddEnabledStateObserver(this);
  62 }
  63
  64 TraceEventSystemStatsMonitor::~TraceEventSystemStatsMonitor() {
  65   if (dump_timer_.IsRunning())
  66     StopProfiling();
  67   TraceLog::GetInstance()->RemoveEnabledStateObserver(this);
  68 }
  69
  70 void TraceEventSystemStatsMonitor::OnTraceLogEnabled() {
  71   // Check to see if system tracing is enabled.
  72   bool enabled;
  73
  74   TRACE_EVENT_CATEGORY_GROUP_ENABLED(TRACE_DISABLED_BY_DEFAULT(
  75                                      "system_stats"), &enabled);
  76   if (!enabled)
  77     return;
  78   task_runner_->PostTask(
  79       FROM_HERE,
  80       base::Bind(&TraceEventSystemStatsMonitor::StartProfiling,
  81                  weak_factory_.GetWeakPtr()));
  82 }
  83
  84 void TraceEventSystemStatsMonitor::OnTraceLogDisabled() {
  85   task_runner_->PostTask(
  86       FROM_HERE,
  87       base::Bind(&TraceEventSystemStatsMonitor::StopProfiling,
  88                  weak_factory_.GetWeakPtr()));
  89 }
  90
  91 void TraceEventSystemStatsMonitor::StartProfiling() {
  92   // Watch for the tracing framework sending enabling more than once.
  93   if (dump_timer_.IsRunning())
  94     return;
  95
  96   dump_timer_.Start(FROM_HERE,
  97                     TimeDelta::FromMilliseconds(TraceEventSystemStatsMonitor::
  98                                                 kSamplingIntervalMilliseconds),
  99                     base::Bind(&TraceEventSystemStatsMonitor::
 100                                DumpSystemStats,
 101                                weak_factory_.GetWeakPtr()));
 102 }
 103
 104 // If system tracing is enabled, dumps a profile to the tracing system.
 105 void TraceEventSystemStatsMonitor::DumpSystemStats() {
 106   scoped_ptr<SystemStatsHolder> dump_holder(new SystemStatsHolder());
 107   dump_holder->GetSystemProfilingStats();
 108
 109   TRACE_EVENT_OBJECT_SNAPSHOT_WITH_ID(
 110       TRACE_DISABLED_BY_DEFAULT("system_stats"),
 111       "base::TraceEventSystemStatsMonitor::SystemStats",
 112       this,
 113       dump_holder.PassAs<base::debug::ConvertableToTraceFormat>());
 114 }
 115
 116 void TraceEventSystemStatsMonitor::StopProfiling() {
 117   dump_timer_.Stop();
 118 }
 119
 120 bool TraceEventSystemStatsMonitor::IsTimerRunningForTest() const {
 121   return dump_timer_.IsRunning();
 122 }
 123
 124 void AppendSystemProfileAsTraceFormat(const SystemMetrics& system_metrics,
 125                                       std::string* output) {
 126   std::string tmp;
 127   base::JSONWriter::Write(system_metrics.ToValue().get(), &tmp);
 128   *output += tmp;
 129 }
 130
 131 }  // namespace debug
 132 }  // namespace base