Chrome tracing for system-wide performance stats.

base/debug/trace_event_system_stats_monitor.cc

+// Copyright 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/debug/trace_event_system_stats_monitor.h"
+
+#include "base/debug/leak_annotations.h"
+#include "base/debug/trace_event.h"
+#include "base/json/json_writer.h"
+#include "base/lazy_instance.h"
+#include "base/logging.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/message_loop/message_loop.h"
+#include "base/strings/string_number_conversions.h"
+#include "base/strings/string_util.h"
+#include "base/threading/thread_local_storage.h"
+
+namespace base {
+namespace debug {
+
+namespace {
+
+/////////////////////////////////////////////////////////////////////////////
+// Holds profiled system stats until the tracing system needs to serialize it.
+class SystemProfilingStats : public base::debug::ConvertableToTraceFormat {
+ public:
+  SystemProfilingStats() { }
+  virtual ~SystemProfilingStats() { }
+
+  // Fills system_stats_ with profiled system memory and disk stats.
+  // Uses the previous stats to compute rates if this is not the first profile.
+  void GetSystemProfilingStats(SystemMetrics* prev_system_metrics,
+                               bool first_profile);
+
+  // base::debug::ConvertableToTraceFormat overrides:
+  virtual void AppendAsTraceFormat(std::string* out) const OVERRIDE {
+    AppendSystemProfileAsTraceFormat(system_metrics_, out);
+  }
+
+ private:
+  SystemMetrics system_metrics_;
+
+  DISALLOW_COPY_AND_ASSIGN(SystemProfilingStats);
+};
+
+void SystemProfilingStats::GetSystemProfilingStats(
+    SystemMetrics* prev_system_metrics, bool first_profile) {
+  system_metrics_ = SystemMetrics::Sample();
+
+  // If this is not the first profile dump, compute rates of change.
+  // Otherwise, stats that are rates remain zero.
+/*

[nduca, 2013/08/28 23:45:40]

dont commit dead code.

[jwmak, 2013/09/06 22:39:37]

Done.

+  if (!first_profile)
+    system_metrics_.ComputeRateMetricsFromPreviousState(
+        *prev_system_metrics,
+        TraceEventSystemStatsMonitor::kSystemStatsMonitorIntervalSeconds);
+*/
+
+  // Save the current non-rate stats for the next profile.
+  *prev_system_metrics = system_metrics_;

[nduca, 2013/08/28 23:45:40]

Remove the prev_blahblah stuff until you add in the deltas in a follwoup patch

[jwmak, 2013/09/06 22:39:37]

Done.

+}
+}  // namespace
+
+//////////////////////////////////////////////////////////////////////////////
+
+TraceEventSystemStatsMonitor::TraceEventSystemStatsMonitor(
+    scoped_refptr<MessageLoopProxy> message_loop_proxy)
+    : message_loop_proxy_(message_loop_proxy),
+      weak_factory_(this) {
+  // Force the "system_memory_and_disk" category to show up in the trace viewer.
+  TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("system_memory_and_disk"), "init");

[nduca, 2013/08/28 23:45:40]

You can do this just by getting the category itself ---
base::Debug::TraceLog()->GetCategorySomethingOrOther(DISABLED_BY_DEFAULT("..."));

[jwmak, 2013/09/06 22:39:37]

Done.

+  // Allow this to be instantiated on unsupported platforms, but don't run.
+  TraceLog::GetInstance()->AddEnabledStateObserver(this);
+}
+
+TraceEventSystemStatsMonitor::~TraceEventSystemStatsMonitor() {
+  if (dump_timer_.IsRunning())
+    StopProfiling();
+  TraceLog::GetInstance()->RemoveEnabledStateObserver(this);
+}
+
+void TraceEventSystemStatsMonitor::OnTraceLogEnabled() {
+  // Check to see if system tracing is enabled.
+  bool enabled;
+
+  TRACE_EVENT_CATEGORY_GROUP_ENABLED(TRACE_DISABLED_BY_DEFAULT(
+                                     "system_memory_and_disk"), &enabled);
+  if (!enabled)
+    return;
+  DVLOG(1) << "OnTraceLogEnabled";

[nduca, 2013/08/28 23:45:40]

dont commit loggin

[jwmak, 2013/09/06 22:39:37]

Done.

+  message_loop_proxy_->PostTask(
+      FROM_HERE,
+      base::Bind(&TraceEventSystemStatsMonitor::StartProfiling,
+                 weak_factory_.GetWeakPtr()));
+}
+
+void TraceEventSystemStatsMonitor::OnTraceLogDisabled() {
+  DVLOG(1) << "OnTraceLogDisabled";
+  message_loop_proxy_->PostTask(
+      FROM_HERE,
+      base::Bind(&TraceEventSystemStatsMonitor::StopProfiling,
+                 weak_factory_.GetWeakPtr()));
+}
+
+void TraceEventSystemStatsMonitor::StartProfiling() {
+  // Watch for the tracing framework sending enabling more than once.
+  if (dump_timer_.IsRunning())
+    return;
+
+  // Do not compute rates of change for the first profile.
+  first_profile_ = true;
+
+  dump_timer_.Start(FROM_HERE,
+                    TimeDelta::FromSeconds(TraceEventSystemStatsMonitor::
+                                           kSystemStatsMonitorIntervalSeconds),
+                    base::Bind(&TraceEventSystemStatsMonitor::
+                               DumpSystemProfile,
+                               weak_factory_.GetWeakPtr()));
+}
+
+// If system tracing is enabled, dumps a profile to the tracing system.
+void TraceEventSystemStatsMonitor::DumpSystemProfile() {
+  DVLOG(1) << "DumpSystemProfile";

[nduca, 2013/08/28 23:45:40]

dont commit logging

[jwmak, 2013/09/06 22:39:37]

Done.

+
+  scoped_ptr<SystemProfilingStats> dump_holder(new SystemProfilingStats());
+  dump_holder->GetSystemProfilingStats(&previous_system_metrics_,
+                                       first_profile_);
+
+  // After the first profile dump, compute rates of change for future dumps.
+  first_profile_ = false;

[nduca, 2013/08/28 23:45:40]

remove this until you add this stuff

[jwmak, 2013/09/06 22:39:37]

Done.

+
+  const int kSnapshotId = 1;
+  TRACE_EVENT_OBJECT_SNAPSHOT_WITH_ID(
+      TRACE_DISABLED_BY_DEFAULT("system_memory_and_disk"),

[nduca, 2013/08/28 23:45:40]

you need a name for this system. oyu're calling it system_Stats some places and
system_memory_and_disk, and in js system stats monitor. I'd suggest
system_stats, and use it everywhere.

[jwmak, 2013/09/06 22:39:37]

Done.

+      "system_stats",

[nduca, 2013/08/28 23:45:40]

this should be base::TraceEventSystemStatsMonitor::SystemStats --- naked names
are discouraged in tracing

[jwmak, 2013/09/06 22:39:37]

Done.

+      kSnapshotId,
+      dump_holder.PassAs<base::debug::ConvertableToTraceFormat>());
+}
+
+void TraceEventSystemStatsMonitor::StopProfiling() {
+  dump_timer_.Stop();
+}
+
+bool TraceEventSystemStatsMonitor::IsTimerRunningForTest() const {
+  return dump_timer_.IsRunning();
+}
+
+void AppendSystemProfileAsTraceFormat(const SystemMetrics& system_metrics,
+                                      std::string* output) {
+  std::string tmp;
+  base::JSONWriter::Write(system_metrics.AsValue(), &tmp);
+  *output += tmp;
+}
+
+}  // namespace debug
+}  // namespace base