Defer low res tile rendering to once/second

bug:6434846
Change-Id: I5ba981e6a3e154a1e99873d8fd5317b8ce7bb73b

6 files changed, 61 insertions, 26 deletions

diff --git a/Source/WebCore/platform/graphics/android/rendering/PaintTileOperation.cpp b/Source/WebCore/platform/graphics/android/rendering/PaintTileOperation.cpp
index 05defc9..87096b0 100644
--- a/Source/WebCore/platform/graphics/android/rendering/PaintTileOperation.cpp
+++ b/Source/WebCore/platform/graphics/android/rendering/PaintTileOperation.cpp
@@ -34,6 +34,7 @@
 #include "ImageTexture.h"
 #include "ImagesManager.h"
 #include "LayerAndroid.h"
+#include "TexturesGenerator.h"
 #include "TilesManager.h"
 
 namespace WebCore {
@@ -89,9 +90,9 @@ int PaintTileOperation::priority()
 
     int priority = 200000;
 
-    // prioritize low res while scrolling
+    // prioritize low res while scrolling, otherwise set priority above gDeferPriorityCutoff
     if (m_isLowResPrefetch)
-        priority = m_state->isScrolling() ? 0 : 400000;
+        priority = m_state->isScrolling() ? 0 : TexturesGenerator::gDeferPriorityCutoff;
 
     // prioritize higher draw count
     unsigned long long currentDraw = TilesManager::instance()->getDrawGLCount();
diff --git a/Source/WebCore/platform/graphics/android/rendering/TexturesGenerator.cpp b/Source/WebCore/platform/graphics/android/rendering/TexturesGenerator.cpp
index dd645d9..cc94c9c 100644
--- a/Source/WebCore/platform/graphics/android/rendering/TexturesGenerator.cpp
+++ b/Source/WebCore/platform/graphics/android/rendering/TexturesGenerator.cpp
@@ -51,12 +51,20 @@ bool TexturesGenerator::tryUpdateOperationWithPainter(Tile* tile, TilePainter* p
 
 void TexturesGenerator::scheduleOperation(QueuedOperation* operation)
 {
+    bool signal = false;
     {
         android::Mutex::Autolock lock(mRequestedOperationsLock);
         mRequestedOperations.append(operation);
         mRequestedOperationsHash.set(operation->uniquePtr(), operation);
+
+        bool deferrable = operation->priority() >= gDeferPriorityCutoff;
+        m_deferredMode &= deferrable;
+
+        // signal if we weren't in deferred mode, or if we can no longer defer
+        signal = !m_deferredMode || !deferrable;
     }
-    mRequestedOperationsCond.signal();
+    if (signal)
+        mRequestedOperationsCond.signal();
 }
 
 void TexturesGenerator::removeOperationsForFilter(OperationFilter* filter)
@@ -115,6 +123,13 @@ QueuedOperation* TexturesGenerator::popNext()
             currentIndex = i;
         }
     }
+
+    if (!m_deferredMode && currentPriority >= gDeferPriorityCutoff) {
+        // finished with non-deferred rendering, enter deferred mode to wait
+        m_deferredMode = true;
+        return 0;
+    }
+
     mRequestedOperations.remove(currentIndex);
     mRequestedOperationsHash.remove(current->uniquePtr());
     return current;
@@ -124,36 +139,46 @@ bool TexturesGenerator::threadLoop()
 {
     // Check if we have any pending operations.
     mRequestedOperationsLock.lock();
-    while (!mRequestedOperations.size())
-        mRequestedOperationsCond.wait(mRequestedOperationsLock);
 
-    ALOGV("threadLoop, got signal");
+    if (!m_deferredMode) {
+        // if we aren't currently deferring work, wait for new work to arrive
+        while (!mRequestedOperations.size())
+            mRequestedOperationsCond.wait(mRequestedOperationsLock);
+    } else {
+        // if we only have deferred work, wait for better work, or a timeout
+        mRequestedOperationsCond.waitRelative(mRequestedOperationsLock, gDeferNsecs);
+    }
+
     mRequestedOperationsLock.unlock();
 
-    m_currentOperation = 0;
     bool stop = false;
     while (!stop) {
+        QueuedOperation* currentOperation = 0;
+
         mRequestedOperationsLock.lock();
         ALOGV("threadLoop, %d operations in the queue", mRequestedOperations.size());
+
         if (mRequestedOperations.size())
-            m_currentOperation = popNext();
+            currentOperation = popNext();
         mRequestedOperationsLock.unlock();
 
-        if (m_currentOperation) {
+        if (currentOperation) {
             ALOGV("threadLoop, painting the request with priority %d",
-                  m_currentOperation->priority());
-            m_currentOperation->run();
+                  currentOperation->priority());
+            currentOperation->run();
         }
 
-        QueuedOperation* oldOperation = m_currentOperation;
         mRequestedOperationsLock.lock();
-        if (m_currentOperation)
-            m_currentOperation = 0;
-        if (!mRequestedOperations.size())
+        if (m_deferredMode && !currentOperation)
             stop = true;
+        if (!mRequestedOperations.size()) {
+            m_deferredMode = false;
+            stop = true;
+        }
         mRequestedOperationsLock.unlock();
-        if (oldOperation)
-            delete oldOperation; // delete outside lock
+
+        if (currentOperation)
+            delete currentOperation; // delete outside lock
     }
     ALOGV("threadLoop empty");
 
diff --git a/Source/WebCore/platform/graphics/android/rendering/TexturesGenerator.h b/Source/WebCore/platform/graphics/android/rendering/TexturesGenerator.h
index bc4fe1e..290ad08 100644
--- a/Source/WebCore/platform/graphics/android/rendering/TexturesGenerator.h
+++ b/Source/WebCore/platform/graphics/android/rendering/TexturesGenerator.h
@@ -44,8 +44,8 @@ class TilesManager;
 class TexturesGenerator : public Thread {
 public:
     TexturesGenerator(TilesManager* instance) : Thread(false)
-        , m_currentOperation(0)
-        , m_tilesManager(instance) { }
+        , m_tilesManager(instance)
+        , m_deferredMode(false) { }
     virtual ~TexturesGenerator() { }
     virtual status_t readyToRun();
 
@@ -55,6 +55,10 @@ public:
 
     void scheduleOperation(QueuedOperation* operation);
 
+    // low res tiles are put at or above this cutoff when not scrolling,
+    // signifying that they should be deferred
+    static const int gDeferPriorityCutoff = 500000000;
+
 private:
     QueuedOperation* popNext();
     virtual bool threadLoop();
@@ -62,8 +66,13 @@ private:
     WTF::HashMap<void*, QueuedOperation*> mRequestedOperationsHash;
     android::Mutex mRequestedOperationsLock;
     android::Condition mRequestedOperationsCond;
-    QueuedOperation* m_currentOperation;
     TilesManager* m_tilesManager;
+
+    bool m_deferredMode;
+
+    // defer painting for one second if best in queue has priority
+    // QueuedOperation::gDeferPriorityCutoff or higher
+    static const nsecs_t gDeferNsecs = 1000000000;
 };
 
 } // namespace WebCore
diff --git a/Source/WebCore/platform/graphics/android/rendering/Tile.cpp b/Source/WebCore/platform/graphics/android/rendering/Tile.cpp
index 2e2c397..e674884 100644
--- a/Source/WebCore/platform/graphics/android/rendering/Tile.cpp
+++ b/Source/WebCore/platform/graphics/android/rendering/Tile.cpp
@@ -54,7 +54,7 @@ Tile::Tile(bool isLayerTile)
     , m_backTexture(0)
     , m_scale(1)
     , m_dirty(true)
-    , m_repaintPending(false)
+    , m_repaintsPending(0)
     , m_fullRepaint(true)
     , m_isLayerTile(isLayerTile)
     , m_drawCount(0)
@@ -212,13 +212,13 @@ bool Tile::isDirty()
 bool Tile::isRepaintPending()
 {
     android::AutoMutex lock(m_atomicSync);
-    return m_repaintPending;
+    return m_repaintsPending != 0;
 }
 
 void Tile::setRepaintPending(bool pending)
 {
     android::AutoMutex lock(m_atomicSync);
-    m_repaintPending = pending;
+    m_repaintsPending += pending ? 1 : -1;
 }
 
 bool Tile::drawGL(float opacity, const SkRect& rect, float scale,
diff --git a/Source/WebCore/platform/graphics/android/rendering/Tile.h b/Source/WebCore/platform/graphics/android/rendering/Tile.h
index 4c8052c..2dc5414 100644
--- a/Source/WebCore/platform/graphics/android/rendering/Tile.h
+++ b/Source/WebCore/platform/graphics/android/rendering/Tile.h
@@ -157,8 +157,8 @@ private:
     // redrawn in the backTexture
     bool m_dirty;
 
-    // used to signal that a repaint is pending
-    bool m_repaintPending;
+    // number of repaints pending
+    int m_repaintsPending;
 
     // store the dirty region
     SkRegion m_dirtyArea;
diff --git a/Source/WebCore/platform/graphics/android/rendering/TileGrid.cpp b/Source/WebCore/platform/graphics/android/rendering/TileGrid.cpp
index d0a9f27..3487acd 100644
--- a/Source/WebCore/platform/graphics/android/rendering/TileGrid.cpp
+++ b/Source/WebCore/platform/graphics/android/rendering/TileGrid.cpp
@@ -248,7 +248,7 @@ void TileGrid::prepareTile(int x, int y, TilePainter* painter,
         if (tile->isRepaintPending() && tilesManager->tryUpdateOperationWithPainter(tile, painter))
             return;
 
-        ALOGV("painting TG %p's tile %d %d for LG %p", this, x, y, painter);
+        ALOGV("painting TG %p's tile %d %d for LG %p, scale %f", this, x, y, painter, m_scale);
         PaintTileOperation *operation = new PaintTileOperation(tile, painter,
                                                                state, isLowResPrefetch);
         tilesManager->scheduleOperation(operation);