base: Move renderer threads to the appropriate cpuset.

content/renderer/render_thread_impl.cc

Index: content/renderer/render_thread_impl.cc
diff --git a/content/renderer/render_thread_impl.cc b/content/renderer/render_thread_impl.cc
index eb7094a55a274d2384e6dd7d58d1202cb82a859a..7c267b35fa6afcdd8e0997e16bafbd8f9635900c 100644
--- a/content/renderer/render_thread_impl.cc
+++ b/content/renderer/render_thread_impl.cc
@@ -858,6 +858,13 @@ void RenderThreadImpl::Init(
   time_zone_monitor->AddClient(
       time_zone_monitor_binding_.CreateInterfacePtrAndBind());
 
+#if defined(OS_LINUX)
+  ChildProcess::current()->SetIOThreadPriority(base::ThreadPriority::DISPLAY);
+  ChildThreadImpl::current()->SetThreadPriority(
+      categorized_worker_pool_->background_worker_thread_id(),

[Nico, 2016/09/19 20:49:30]

Doesn't the worker pool have more than one id?

[reveman, 2016/09/19 21:43:39]

It has a single thread for background work and N number of threads for
foreground work. Reducing the priority of the thread for background work is
useful to ensure that things like prepaint of contents far away from the
viewport doesn't result in unnecessary power usage or missed frames. 

+      base::ThreadPriority::BACKGROUND);
+#endif
+
   is_renderer_suspended_ = false;
 }
 
@@ -1134,6 +1141,10 @@ void RenderThreadImpl::InitializeCompositorThread() {
   compositor_task_runner_->PostTask(
       FROM_HERE,
       base::Bind(base::IgnoreResult(&ThreadRestrictions::SetIOAllowed), false));
+#if defined(OS_LINUX)
+  ChildThreadImpl::current()->SetThreadPriority(compositor_thread_->threadId(),
+                                                base::ThreadPriority::DISPLAY);
+#endif
 
   SynchronousInputHandlerProxyClient* synchronous_input_handler_proxy_client =
       nullptr;