Reland "Throttle resource message requests during user interaction"

content/renderer/render_thread_impl.cc

 // Copyright (c) 2012 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/render_thread_impl.h"
 
 #include <algorithm>
 #include <limits>
 #include <map>
 #include <vector>
@@ skipping 85 matching lines @@
 #include "content/renderer/media/render_media_client.h"
 #include "content/renderer/media/renderer_gpu_video_accelerator_factories.h"
 #include "content/renderer/media/video_capture_impl_manager.h"
 #include "content/renderer/media/video_capture_message_filter.h"
 #include "content/renderer/net_info_helper.h"
 #include "content/renderer/p2p/socket_dispatcher.h"
 #include "content/renderer/render_frame_proxy.h"
 #include "content/renderer/render_process_impl.h"
 #include "content/renderer/render_view_impl.h"
 #include "content/renderer/renderer_blink_platform_impl.h"
+#include "content/renderer/resource_dispatch_throttler.h"
 #include "content/renderer/scheduler/renderer_scheduler.h"
 #include "content/renderer/service_worker/embedded_worker_context_message_filter.h"
 #include "content/renderer/service_worker/embedded_worker_dispatcher.h"
 #include "content/renderer/shared_worker/embedded_shared_worker_stub.h"
 #include "gin/public/debug.h"
 #include "gpu/GLES2/gl2extchromium.h"
 #include "gpu/command_buffer/common/gles2_cmd_utils.h"
 #include "ipc/ipc_channel_handle.h"
 #include "ipc/ipc_platform_file.h"
 #include "ipc/mojo/ipc_channel_mojo.h"
@@ skipping 72 matching lines @@
 using blink::WebString;
 using blink::WebView;
 
 namespace content {
 
 namespace {
 
 const int64 kInitialIdleHandlerDelayMs = 1000;
 const int64 kLongIdleHandlerDelayMs = 30*1000;
 
+#if defined(OS_ANDROID)
+// On Android, resource messages can each take ~1.5ms to dispatch on the browser
+// IO thread. Limiting the message rate to 3/frame at 60hz ensures that the
+// induced work takes but a fraction (~1/4) of the overall frame budget.
+const int kMaxResourceRequestsPerFlushWhenThrottled = 3;
+#else
+const int kMaxResourceRequestsPerFlushWhenThrottled = 8;
+#endif
+const double kThrottledResourceRequestFlushPeriodS = 1. / 60.;
+
 // Maximum allocation size allowed for image scaling filters that
 // require pre-scaling. Skia will fallback to a filter that doesn't
 // require pre-scaling if the default filter would require an
 // allocation that exceeds this limit.
 const size_t kImageCacheSingleAllocationByteLimit = 64 * 1024 * 1024;
 
 const size_t kEmulatedDiscardableMemoryBytesToKeepWhenWidgetsHidden =
     4 * 1024 * 1024;
 
 // Keep the global RenderThreadImpl in a TLS slot so it is impossible to access
@@ skipping 263 matching lines @@
 
   appcache_dispatcher_.reset(
       new AppCacheDispatcher(Get(), new AppCacheFrontendImpl()));
   dom_storage_dispatcher_.reset(new DomStorageDispatcher());
   main_thread_indexed_db_dispatcher_.reset(new IndexedDBDispatcher(
       thread_safe_sender()));
   renderer_scheduler_ = RendererScheduler::Create();
   channel()->SetListenerTaskRunner(renderer_scheduler_->DefaultTaskRunner());
   embedded_worker_dispatcher_.reset(new EmbeddedWorkerDispatcher());
 
+  resource_dispatch_throttler_.reset(new ResourceDispatchThrottler(

[alex clarke (OOO till 29th), 2015/01/26 17:15:59]

I wonder if we should have a FIXME comment since in an ideal world all
operations on the the IO thread would be fast and we wouldn't need to do this.

[jdduke (slow), 2015/01/26 20:14:48]

That's a good point, yeah, I'll put a note in ResourceDispatchThrottler that it
should eventually go away entirely.

+      static_cast<RenderThread*>(this), renderer_scheduler_.get(),
+      base::TimeDelta::FromSecondsD(kThrottledResourceRequestFlushPeriodS),
+      kMaxResourceRequestsPerFlushWhenThrottled));
+  resource_dispatcher()->set_message_sender(resource_dispatch_throttler_.get());
+
   media_stream_center_ = NULL;
 
   db_message_filter_ = new DBMessageFilter();
   AddFilter(db_message_filter_.get());
 
   vc_manager_.reset(new VideoCaptureImplManager());
   AddFilter(vc_manager_->video_capture_message_filter());
 
   browser_plugin_manager_.reset(new BrowserPluginManager());
   AddObserver(browser_plugin_manager_.get());
@@ skipping 1284 matching lines @@
   hidden_widget_count_--;
 
   if (!GetContentClient()->renderer()->RunIdleHandlerWhenWidgetsHidden()) {
     return;
   }
 
   ScheduleIdleHandler(kLongIdleHandlerDelayMs);
 }
 
 }  // namespace content