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      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 
     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::debug::ConvertableToTraceFormat overrides:
     34   virtual void AppendAsTraceFormat(std::string* out) const OVERRIDE {
     35     AppendSystemProfileAsTraceFormat(system_stats_, out);
     36   }
     37 
     38  private:
     39   virtual ~SystemStatsHolder() { }
     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().get(), &tmp);
    129   *output += tmp;
    130 }
    131 
    132 }  // namespace debug
    133 }  // namespace base
    134