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