Add V8 heap statistics in a time-line manner in tracing.

content/renderer/v8_heap_statistics_collector_impl.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 "content/renderer/v8_heap_statistics_collector_impl.h"
+
+#include "base/bind.h"
+#include "base/message_loop/message_loop_proxy.h"
+#include "content/renderer/render_thread_impl.h"
+#include "v8/include/v8.h"
+
+namespace content {
+
+static const int kWaitForWorkersStatsTimeoutMS = 20;
+
+V8HeapStatisticsCollector* V8HeapStatisticsCollector::Instance() {
+  return V8HeapStatisticsCollectorImpl::Instance();
+}
+
+V8HeapStatisticsCollector* V8HeapStatisticsCollectorImpl::Instance() {
+  CR_DEFINE_STATIC_LOCAL(V8HeapStatisticsCollectorImpl, instance, ());
+  return &instance;
+}
+
+V8HeapStatisticsCollectorImpl::V8HeapStatisticsCollectorImpl()
+    : round_id_(0) {}
+
+V8HeapStatisticsCollectorImpl::~V8HeapStatisticsCollectorImpl() {
+}
+
+bool V8HeapStatisticsCollectorImpl::InitiateCollection(
+    const ResultCallback& callback) {
+  DCHECK(RenderThreadImpl::Get());
+  if (pending_result_callback_)
+    return false;
+  pending_result_callback_.reset(new ResultCallback(callback));
+
+  v8::HeapStatistics heap_stats;
+  v8::Isolate::GetCurrent()->GetHeapStatistics(&heap_stats);
+  pending_stats_.total_bytes = heap_stats.total_heap_size();
+  pending_stats_.used_bytes = heap_stats.used_heap_size();
+  base::Closure collect = base::Bind(
+      &V8HeapStatisticsCollectorImpl::CollectOnWorkerThread,
+      base::Unretained(this),
+      base::MessageLoopProxy::current(),
+      round_id_);
+  workers_to_go_ = RenderThreadImpl::Get()->PostTaskToAllWebWorkers(collect);
+  if (workers_to_go_) {
+    // The guard task to send out partial stats
+    // in case some workers are not responsive.
+    base::MessageLoopProxy::current()->PostDelayedTask(
+        FROM_HERE,
+        base::Bind(&V8HeapStatisticsCollectorImpl::SendStatsToCallback,
+                   base::Unretained(this),
+                   round_id_),
+        base::TimeDelta::FromMilliseconds(kWaitForWorkersStatsTimeoutMS));
+  } else {
+    // No worker threads so just send out the main thread data immediately, via
+    // a postTask so that the behavior of sync completion matches the
+    // asynchronous behavior.
+    base::MessageLoopProxy::current()->PostTask(
+        FROM_HERE,
+        base::Bind(&V8HeapStatisticsCollectorImpl::SendStatsToCallback,
+                   base::Unretained(this),
+                   round_id_));
+  }
+  return true;
+}
+
+void V8HeapStatisticsCollectorImpl::CollectOnWorkerThread(
+    scoped_refptr<base::TaskRunner> master,
+    int round_id) {
+
+  size_t total_bytes = 0;
+  size_t used_bytes = 0;
+  v8::Isolate* isolate = v8::Isolate::GetCurrent();
+  if (isolate) {
+    v8::HeapStatistics heap_stats;
+    isolate->GetHeapStatistics(&heap_stats);
+    total_bytes = heap_stats.total_heap_size();
+    used_bytes = heap_stats.used_heap_size();
+  }
+  master->PostTask(
+      FROM_HERE,
+      base::Bind(&V8HeapStatisticsCollectorImpl::ReceiveStats,
+                 base::Unretained(this),
+                 round_id,
+                 total_bytes,
+                 used_bytes));
+}
+
+void V8HeapStatisticsCollectorImpl::ReceiveStats(int round_id,
+                                           size_t total_bytes,
+                                           size_t used_bytes) {
+  if (round_id != round_id_)
+    return;
+  pending_stats_.total_bytes += total_bytes;
+  pending_stats_.used_bytes += used_bytes;
+  if (!--workers_to_go_)
+    SendStatsToCallback(round_id);
+}
+
+void V8HeapStatisticsCollectorImpl::SendStatsToCallback(int round_id) {
+  if (round_id != round_id_)
+    return;
+
+  // TODO(alph): Do caching heap stats and use the cache if we haven't got
+  //             reply from a worker.
+  //             Currently a busy worker stats are not counted.
+  pending_result_callback_->Run(pending_stats_);
+  pending_result_callback_.reset();
+  ++round_id_;
+}
+
+}  // namespace content