Don't spam the GPU process with memory usage stats

cc/layer_tree_host_impl.cc

 // Copyright 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 "cc/layer_tree_host_impl.h"
 
 #include <algorithm>
 
 #include "base/basictypes.h"
 #include "base/debug/trace_event.h"
@@ skipping 209 matching lines @@
                             PriorityCalculator::allowNothingCutoff())
     , m_backgroundColor(0)
     , m_hasTransparentBackground(false)
     , m_needsAnimateLayers(false)
     , m_pinchGestureActive(false)
     , m_fpsCounter(FrameRateCounter::create(m_proxy->hasImplThread()))
     , m_debugRectHistory(DebugRectHistory::create())
     , m_numImplThreadScrolls(0)
     , m_numMainThreadScrolls(0)
     , m_cumulativeNumLayersDrawn(0)
+    , m_lastSentMemoryVisibleBytes(0)
+    , m_lastSentMemoryVisibleAndNearbyBytes(0)
+    , m_lastSentMemoryUseBytes(0)
 {
     DCHECK(m_proxy->isImplThread());
     didVisibilityChange(this, m_visible);
 }
 
 LayerTreeHostImpl::~LayerTreeHostImpl()
 {
     DCHECK(m_proxy->isImplThread());
     TRACE_EVENT0("cc", "LayerTreeHostImpl::~LayerTreeHostImpl()");
 
@@ skipping 1372 matching lines @@
     stats->numFramesSentToScreen = fpsCounter()->currentFrameNumber();
     stats->droppedFrameCount = fpsCounter()->droppedFrameCount();
     stats->numImplThreadScrolls = m_numImplThreadScrolls;
     stats->numMainThreadScrolls = m_numMainThreadScrolls;
     stats->numLayersDrawn = m_cumulativeNumLayersDrawn;
 
     if (m_tileManager)
         m_tileManager->renderingStats(stats);
 }
 
+void LayerTreeHostImpl::sendManagedMemoryStats(
+    size_t memoryVisibleBytes,
+    size_t memoryVisibleAndNearbyBytes,
+    size_t memoryUseBytes)
+{
+    if (!renderer())
+      return;
+
+    // Round the numbers being sent up to the next 8MB, to throttle the rate

[ccameron, 2012/12/07 21:58:41]

Do we have a ROUND_UP macro, or something like that?

+    // at which we spam the GPU process.
+    const size_t roundingStep = 8 * 1024 * 1024;
+    memoryVisibleBytes = ((memoryVisibleBytes + roundingStep - 1) / roundingStep) * roundingStep;
+    memoryVisibleAndNearbyBytes = ((memoryVisibleAndNearbyBytes + roundingStep - 1) / roundingStep) * roundingStep;
+    memoryUseBytes = ((memoryUseBytes + roundingStep - 1) / roundingStep) * roundingStep;
+    if (m_lastSentMemoryVisibleBytes == memoryVisibleBytes &&

[jamesr, 2012/12/07 22:14:34]

alternately, why not just calculate a diff from the last value sent and send
again if it's >= threshold? avoids the rounding math completely

[ccameron, 2012/12/07 22:33:49]

The is less artifact-prone (it doesn't depend on the previous state). It also
always errors on being high.

+        m_lastSentMemoryVisibleAndNearbyBytes == memoryVisibleAndNearbyBytes &&
+        m_lastSentMemoryUseBytes == memoryUseBytes) {
+        return;
+    }
+    m_lastSentMemoryVisibleBytes = memoryVisibleBytes;
+    m_lastSentMemoryVisibleAndNearbyBytes = memoryVisibleAndNearbyBytes;
+    m_lastSentMemoryUseBytes = memoryUseBytes;
+
+    renderer()->sendManagedMemoryStats(m_lastSentMemoryVisibleBytes,
+                                       m_lastSentMemoryVisibleAndNearbyBytes,
+                                       m_lastSentMemoryUseBytes);
+}
+
 void LayerTreeHostImpl::animateScrollbars(base::TimeTicks time)
 {
     animateScrollbarsRecursive(m_rootLayerImpl.get(), time);
 }
 
 void LayerTreeHostImpl::animateScrollbarsRecursive(LayerImpl* layer, base::TimeTicks time)
 {
     if (!layer)
         return;
 
     ScrollbarAnimationController* scrollbarController = layer->scrollbarAnimationController();
     double monotonicTime = (time - base::TimeTicks()).InSecondsF();
     if (scrollbarController && scrollbarController->animate(monotonicTime))
         m_client->setNeedsRedrawOnImplThread();
 
     for (size_t i = 0; i < layer->children().size(); ++i)
         animateScrollbarsRecursive(layer->children()[i], time);
 }
 
 }  // namespace cc