When --disable-gpu-vsync, run requestAnimFrame callbacks at top speed.

content/renderer/render_widget.cc

 // Copyright (c) 2011 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_widget.h"
 
 #include "base/command_line.h"
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
@@ skipping 12 matching lines @@
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebCursorInfo.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebPopupMenu.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebPopupMenuInfo.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebRange.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebRect.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebScreenInfo.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebSize.h"
 #include "ui/gfx/point.h"
 #include "ui/gfx/size.h"
 #include "ui/gfx/surface/transport_dib.h"
+#include "ui/gfx/gl/gl_switches.h"
 #include "webkit/glue/webkit_glue.h"
 #include "webkit/plugins/npapi/webplugin.h"
 #include "webkit/plugins/ppapi/ppapi_plugin_instance.h"
 
 #if defined(OS_POSIX)
 #include "ipc/ipc_channel_posix.h"
 #include "third_party/skia/include/core/SkPixelRef.h"
 #include "third_party/skia/include/core/SkMallocPixelRef.h"
 #endif  // defined(OS_POSIX)
 
@@ skipping 535 matching lines @@
 
   SkIRect irect;
   irect.set(rect.x(), rect.y(), rect.right() - 1, rect.bottom() - 1);
   canvas->drawIRect(irect, paint);
 }
 
 void RenderWidget::AnimationCallback() {
   animation_task_posted_ = false;
   if (!animation_update_pending_)
     return;
-  if (!animation_floor_time_.is_null()) {
+  if (!animation_floor_time_.is_null() && IsRenderingVSyncd()) {
     // Record when we fired (according to base::Time::Now()) relative to when
     // we posted the task to quantify how much the base::Time/base::TimeTicks
     // skew is affecting animations.
     base::TimeDelta animation_callback_delay = base::Time::Now() -
         (animation_floor_time_ - base::TimeDelta::FromMilliseconds(16));
     UMA_HISTOGRAM_CUSTOM_TIMES("Renderer4.AnimationCallbackDelayTime",
                                animation_callback_delay,
                                base::TimeDelta::FromMilliseconds(0),
                                base::TimeDelta::FromMilliseconds(30),
                                25);
   }
   DoDeferredUpdateAndSendInputAck();
 }
 
 void RenderWidget::AnimateIfNeeded() {
   if (!animation_update_pending_)
     return;
+
+  // Target 60FPS if vsync is on. Go as fast as we can if vsync is off.
+  int animationInterval = IsRenderingVSyncd() ? 16 : 0;
+
   base::Time now = base::Time::Now();
   if (now >= animation_floor_time_) {
-    animation_floor_time_ = now + base::TimeDelta::FromMilliseconds(16);
-    // Set a timer to call us back after 16ms (targetting 60FPS) before
+    animation_floor_time_ = now +
+        base::TimeDelta::FromMilliseconds(animationInterval);
+    // Set a timer to call us back after animationInterval before
     // running animation callbacks so that if a callback requests another
     // we'll be sure to run it at the proper time.
     MessageLoop::current()->PostDelayedTask(FROM_HERE, NewRunnableMethod(
-        this, &RenderWidget::AnimationCallback), 16);
+        this, &RenderWidget::AnimationCallback), animationInterval);
     animation_task_posted_ = true;
     animation_update_pending_ = false;
 #ifdef WEBWIDGET_HAS_ANIMATE_CHANGES
     webwidget_->animate(0.0);
 #else
     webwidget_->animate();
 #endif
     return;
   }
+  TRACE_EVENT0("renderer", "EarlyOut_AnimatedTooRecently");
   if (animation_task_posted_)
     return;
   // This code uses base::Time::Now() to calculate the floor and next fire
   // time because javascript's Date object uses base::Time::Now().  The
   // message loop uses base::TimeTicks, which on windows can have a
   // different granularity than base::Time.
   // The upshot of all this is that this function might be called before
   // base::Time::Now() has advanced past the animation_floor_time_.  To
   // avoid exposing this delay to javascript, we keep posting delayed
   // tasks until base::Time::Now() has advanced far enough.
   int64 delay = (animation_floor_time_ - now).InMillisecondsRoundedUp();
   animation_task_posted_ = true;
   MessageLoop::current()->PostDelayedTask(FROM_HERE,
       NewRunnableMethod(this, &RenderWidget::AnimationCallback), delay);
 }
 
+bool RenderWidget::IsRenderingVSyncd() {
+  // TODO(nduca): Forcing a driver to disable vsync (e.g. in a control panel) is
+  // not caught by this check. This will lead to artificially low frame rates
+  // for people who force vsync off at a driver level and expect Chrome to speed
+  // up.
+  return !CommandLine::ForCurrentProcess()->HasSwitch(

[jamesr, 2011/06/02 22:07:53]

nitpick: this is doing a string comparison (and a conversion to lowercase on
windows) on every tick, which with vsync off will be pretty often.  this value
can never change for the lifetime of the process, so could you stash the results
in a static bool and just return that?  the command line strings can be pretty
long sometimes

+      switches::kDisableGpuVsync);
+}
+
 void RenderWidget::InvalidationCallback() {
   invalidation_task_posted_ = false;
   DoDeferredUpdateAndSendInputAck();
 }
 
 void RenderWidget::DoDeferredUpdateAndSendInputAck() {
   DoDeferredUpdate();
 
   if (pending_input_event_ack_.get())
     Send(pending_input_event_ack_.release());
@@ skipping 657 matching lines @@
 
 void RenderWidget::CleanupWindowInPluginMoves(gfx::PluginWindowHandle window) {
   for (WebPluginGeometryVector::iterator i = plugin_window_moves_.begin();
        i != plugin_window_moves_.end(); ++i) {
     if (i->window == window) {
       plugin_window_moves_.erase(i);
       break;
     }
   }
 }