Adaptively throttle texture uploads

cc/CCTextureUpdateController.cpp

 // Copyright 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 "config.h"
 
 #include "CCTextureUpdateController.h"
 
 #include "GraphicsContext3D.h"
 #include "TextureCopier.h"
 #include "TextureUploader.h"
+#include "TraceEvent.h"
+#include <limits>
 #include <wtf/CurrentTime.h>
 
 namespace {
 
-// Number of textures to update with each call to updateMoreTexturesIfEnoughTimeRemaining().
-static const size_t textureUpdatesPerTick = 12;
+static const size_t pixelsPerTexture = 256 * 256;
+
+// Minimum number of textures to update with each call to updateMoreTexturesIfEnoughTimeRemaining().
+static const size_t textureUpdatesPerFullTickMin = 12;
 
 // Measured in seconds.
 static const double textureUpdateTickRate = 0.004;
 
 // Flush interval when performing texture uploads.
 static const int textureUploadFlushPeriod = 4;
 
 } // anonymous namespace
 
 namespace WebCore {
 
-size_t CCTextureUpdateController::maxPartialTextureUpdates()
+size_t CCTextureUpdateController::maxTextureUpdates(TextureUploader* uploader)
 {
-    return textureUpdatesPerTick;
+    double texturesPerSecond = uploader->estimatedPixelsPerSecond() / pixelsPerTexture;
+
+    return std::max(textureUpdatesPerFullTickMin,
+                    (size_t) floor(textureUpdateTickRate * texturesPerSecond));
+}
+
+PassOwnPtr<CCTextureUpdateController> CCTextureUpdateController::create(CCThread* thread, PassOwnPtr<CCTextureUpdateQueue> queue, CCResourceProvider* resourceProvider, TextureCopier* copier, TextureUploader* uploader, size_t maxTextureUpdates)
+{
+    return adoptPtr(new CCTextureUpdateController(thread, queue, resourceProvider, copier, uploader, maxTextureUpdates));
 }
 
 void CCTextureUpdateController::updateTextures(CCResourceProvider* resourceProvider, TextureCopier* copier, TextureUploader* uploader, CCTextureUpdateQueue* queue, size_t count)
 {
     if (queue->fullUploadSize() || queue->partialUploadSize()) {
         if (uploader->isBusy())
             return;
 
         uploader->beginUploads();
 
         size_t fullUploadCount = 0;
-        while (queue->fullUploadSize() && fullUploadCount < count) {
+        bool uploadMore = queue->fullUploadSize() && fullUploadCount < count;
+        while (uploadMore) {
             uploader->uploadTexture(resourceProvider, queue->takeFirstFullUpload());
             fullUploadCount++;
-            if (!(fullUploadCount % textureUploadFlushPeriod))
+            uploadMore = queue->fullUploadSize() && fullUploadCount < count;
+
+            // Flush periodically, but deffer our last flush until after uploader->endUploads()
+            // in order to keep the query associated with endUploads grouped with our last texture upload.
+            if (!(fullUploadCount % textureUploadFlushPeriod) && uploadMore)
                 resourceProvider->shallowFlushIfSupported();
         }
 
-        // Make sure there are no dangling uploads without a flush.
-        if (fullUploadCount % textureUploadFlushPeriod)
+        ASSERT(queue->partialUploadSize() <= count);
+        bool needAnotherTick = queue->fullUploadSize() || ((count - fullUploadCount) < queue->partialUploadSize());
+        if (needAnotherTick) {
+            uploader->endUploads();
             resourceProvider->shallowFlushIfSupported();
-
-        bool moreUploads = queue->fullUploadSize();
-
-        ASSERT(queue->partialUploadSize() <= count);
-        // We need another update batch if the number of updates remaining
-        // in |count| is greater than the remaining partial entries.
-        if ((count - fullUploadCount) < queue->partialUploadSize())
-            moreUploads = true;
-
-        if (moreUploads) {
-            uploader->endUploads();
             return;
         }
+        resourceProvider->shallowFlushIfSupported();
 
         size_t partialUploadCount = 0;
         while (queue->partialUploadSize()) {
             uploader->uploadTexture(resourceProvider, queue->takeFirstPartialUpload());
             partialUploadCount++;
-            if (!(partialUploadCount % textureUploadFlushPeriod))
+            
+            // Flush periodically, but deffer our last flush until after uploader->endUploads()
+            // in order to keep the query associated with endUploads grouped with our last texture upload.
+            if (!(partialUploadCount % textureUploadFlushPeriod) && queue->partialUploadSize())
                 resourceProvider->shallowFlushIfSupported();
         }
 
-        // Make sure there are no dangling partial uploads without a flush.
-        if (partialUploadCount % textureUploadFlushPeriod)
-            resourceProvider->shallowFlushIfSupported();
-
         uploader->endUploads();
+        resourceProvider->shallowFlushIfSupported();
     }
 
     size_t copyCount = 0;
     while (queue->copySize()) {
         copier->copyTexture(queue->takeFirstCopy());
         copyCount++;
     }
 
     // If we've performed any texture copies, we need to insert a flush here into the compositor context
     // before letting the main thread proceed as it may make draw calls to the source texture of one of
     // our copy operations.
     if (copyCount)
         copier->flush();
 }
 
-CCTextureUpdateController::CCTextureUpdateController(CCThread* thread, PassOwnPtr<CCTextureUpdateQueue> queue, CCResourceProvider* resourceProvider, TextureCopier* copier, TextureUploader* uploader)
+CCTextureUpdateController::CCTextureUpdateController(CCThread* thread, PassOwnPtr<CCTextureUpdateQueue> queue, CCResourceProvider* resourceProvider, TextureCopier* copier, TextureUploader* uploader, size_t maxTextureUpdates)
     : m_timer(adoptPtr(new CCTimer(thread, this)))
     , m_queue(queue)
     , m_resourceProvider(resourceProvider)
     , m_copier(copier)
     , m_uploader(uploader)
     , m_monotonicTimeLimit(0)
+    , m_textureUpdatesPerTick(maxTextureUpdates)
     , m_firstUpdateAttempt(true)
 {
 }
 
 CCTextureUpdateController::~CCTextureUpdateController()
 {
 }
 
 bool CCTextureUpdateController::hasMoreUpdates() const
 {
     return m_queue->hasMoreUpdates();
 }
 
 void CCTextureUpdateController::updateMoreTextures(double monotonicTimeLimit)
 {
     m_monotonicTimeLimit = monotonicTimeLimit;
 
     if (!m_queue->hasMoreUpdates())
         return;
 
     // Call updateMoreTexturesNow() directly unless it's the first update
     // attempt. This ensures that we empty the update queue in a finite
     // amount of time.
     if (m_firstUpdateAttempt) {
         updateMoreTexturesIfEnoughTimeRemaining();
         m_firstUpdateAttempt = false;
     } else
         updateMoreTexturesNow();
+
 }
 
 void CCTextureUpdateController::onTimerFired()
 {
     if (!m_queue->hasMoreUpdates())
         return;
 
     updateMoreTexturesIfEnoughTimeRemaining();
 }
 
 double CCTextureUpdateController::monotonicTimeNow() const
 {
     return monotonicallyIncreasingTime();
 }
 
 double CCTextureUpdateController::updateMoreTexturesTime() const
 {
     return textureUpdateTickRate;
 }
 
 size_t CCTextureUpdateController::updateMoreTexturesSize() const
 {
-    return textureUpdatesPerTick;
+    return m_textureUpdatesPerTick;
 }
 
 void CCTextureUpdateController::updateMoreTexturesIfEnoughTimeRemaining()
 {
     bool hasTimeRemaining = monotonicTimeNow() < m_monotonicTimeLimit - updateMoreTexturesTime();
     if (hasTimeRemaining)
         updateMoreTexturesNow();
 }
 
 void CCTextureUpdateController::updateMoreTexturesNow()
 {
     m_timer->startOneShot(updateMoreTexturesTime());
     updateTextures(m_resourceProvider, m_copier, m_uploader, m_queue.get(), updateMoreTexturesSize());
 }
 
 }