Bag of scheduling tweaks

 Bug: 15118640

 * Prevent over-stuffing the queue by dropping frames
 * Prevent double-drawing in one pulse by RT by deferring
   vsync registration until post-draw so that it catches
   the next vsync pulse instead of the current one
 * Bias vsync race condition towards the UI thread
 * Fix queueDelay to actually work

Change-Id: Ibf584258bd93ebcbba058bd976dc8b307f1c6155

1 files changed, 8 insertions, 0 deletions

diff --git a/libs/hwui/TreeInfo.h b/libs/hwui/TreeInfo.h
index d4a23b878390..8355f83ea37c 100644
--- a/libs/hwui/TreeInfo.h
+++ b/libs/hwui/TreeInfo.h
@@ -52,6 +52,7 @@ struct TreeInfo {
             : hasFunctors(false)
             , hasAnimations(false)
             , requiresUiRedraw(false)
+            , canDrawThisFrame(true)
         {}
         bool hasFunctors;
         // This is only updated if evaluateAnimations is true
@@ -60,6 +61,13 @@ struct TreeInfo {
         // animate itself, such as if hasFunctors is true
         // This is only set if hasAnimations is true
         bool requiresUiRedraw;
+        // This is set to true if draw() can be called this frame
+        // false means that we must delay until the next vsync pulse as frame
+        // production is outrunning consumption
+        // NOTE that if this is false CanvasContext will set either requiresUiRedraw
+        // *OR* will post itself for the next vsync automatically, use this
+        // only to avoid calling draw()
+        bool canDrawThisFrame;
     } out;
 
     // TODO: Damage calculations