cc: Set the mapped memory reclaim limit for the renderer compositor on Android

content/renderer/render_widget.cc

Index: content/renderer/render_widget.cc
diff --git a/content/renderer/render_widget.cc b/content/renderer/render_widget.cc
index 0f3d037e01178c8a8f87537bb631774f97193678..5f392367254c2b31f9deeb0e1b683ba8899a2fdd 100644
--- a/content/renderer/render_widget.cc
+++ b/content/renderer/render_widget.cc
@@ -62,6 +62,7 @@
 #include "webkit/renderer/compositor_bindings/web_rendering_stats_impl.h"
 
 #if defined(OS_ANDROID)
+#include "base/android/sys_utils.h"
 #include "content/renderer/android/synchronous_compositor_factory.h"
 #endif
 
@@ -647,17 +648,14 @@ bool RenderWidget::ForceCompositingModeEnabled() {
 }
 
 scoped_ptr<cc::OutputSurface> RenderWidget::CreateOutputSurface(bool fallback) {
-  const CommandLine& command_line = *CommandLine::ForCurrentProcess();
 
 #if defined(OS_ANDROID)
-   if (SynchronousCompositorFactory* factory =
-       SynchronousCompositorFactory::GetInstance()) {
+  if (SynchronousCompositorFactory* factory =
+      SynchronousCompositorFactory::GetInstance()) {
     return factory->CreateOutputSurface(routing_id());
   }
 #endif
 
-  uint32 output_surface_id = next_output_surface_id_++;
-
   // Explicitly disable antialiasing for the compositor. As of the time of
   // this writing, the only platform that supported antialiasing for the
   // compositor was Mac OS X, because the on-screen OpenGL context creation
@@ -674,14 +672,40 @@ scoped_ptr<cc::OutputSurface> RenderWidget::CreateOutputSurface(bool fallback) {
   attributes.noAutomaticFlushes = true;
   attributes.depth = false;
   attributes.stencil = false;
+
+  const CommandLine& command_line = *CommandLine::ForCurrentProcess();
   if (command_line.HasSwitch(cc::switches::kForceDirectLayerDrawing))
     attributes.stencil = true;
+
   scoped_refptr<ContextProviderCommandBuffer> context_provider;
   if (!fallback) {
+    // If we raster too fast we become upload bound, and pending

[danakj, 2013/08/29 20:10:28]

Any reason to do this here instead of inside CreateGraphicsContext3D?

[kaanb, 2013/08/30 01:11:35]

Done.

+    // uploads consume memory. For maximum upload throughput, we would
+    // want to allow for upload_throughput * pipeline_time of pending
+    // uploads, after which we are just wasting memory. Since we don't
+    // know our upload throughput yet, this just caps our memory usage.
+#if defined(OS_ANDROID)
+    size_t divider = 1;
+    if (base::android::SysUtils::IsLowEndDevice())
+      divider = 3;
+
+    // For reference Nexus10 can upload 1MB in about 2.5ms.
+    const size_t kMaxBytesUploadedPerMs = (2 * 1024 * 1024) / (5 * divider);
+#else
+    // For reference Chromebook Pixel can upload 1MB in about 0.5ms.

[piman, 2013/08/29 21:58:19]

This affects more than the Pixel. It affects the context on all non-android
devices (including desktop).
I feel uncomfortable limiting the mapped memory everywhere with this CL, it
hasn't been a (large) problem beyond Android so far. Other platforms
aggressively free mapped memory as we switch tabs, and that seems to be enough.

[kaanb, 2013/08/30 01:11:35]

Please note that this constant also eventually makes it to the
PixelBufferRasterWorkerPool. I added an ifdef to WGC3DCBI to only set the GL
mapped memory limit for Android.

+    const size_t kMaxBytesUploadedPerMs = 1024 * 1024 * 2;
+#endif
+
+    // Assuming a two frame deep pipeline.

[piman, 2013/08/29 21:58:19]

Between what and what?

[kaanb, 2013/08/30 01:11:35]

Done.

+    const size_t kMsPerFrame = 16;

[piman, 2013/08/29 21:58:19]

What is this number?

[kaanb, 2013/08/30 01:11:35]

Done.

+    const size_t max_transfer_buffer_usage_bytes =

[danakj, 2013/08/29 20:10:28]

nit: no const, or kMaxTransferBufferUsageBytes.

[kaanb, 2013/08/30 01:11:35]

Done.

+        2 * kMsPerFrame * kMaxBytesUploadedPerMs;
+
     context_provider = ContextProviderCommandBuffer::Create(
-        CreateGraphicsContext3D(attributes));
+        CreateGraphicsContext3D(attributes, max_transfer_buffer_usage_bytes));
   }
 
+  uint32 output_surface_id = next_output_surface_id_++;
   if (!context_provider.get()) {
     if (!command_line.HasSwitch(switches::kEnableSoftwareCompositing))
       return scoped_ptr<cc::OutputSurface>();
@@ -2510,7 +2534,8 @@ bool RenderWidget::HasTouchEventHandlersAt(const gfx::Point& point) const {
 
 scoped_ptr<WebGraphicsContext3DCommandBufferImpl>
 RenderWidget::CreateGraphicsContext3D(
-    const WebKit::WebGraphicsContext3D::Attributes& attributes) {
+    const WebKit::WebGraphicsContext3D::Attributes& attributes,
+    size_t max_bytes_pending_upload) {
   if (!webwidget_)
     return scoped_ptr<WebGraphicsContext3DCommandBufferImpl>();
   if (CommandLine::ForCurrentProcess()->HasSwitch(
@@ -2523,10 +2548,19 @@ RenderWidget::CreateGraphicsContext3D(
           RenderThreadImpl::current(),
           weak_ptr_factory_.GetWeakPtr()));
 
-  if (!context->InitializeWithDefaultBufferSizes(
+  // We keep the MappedMemoryReclaimLimit the same as the upload limit
+  // to avoid unnecessarily stalling the compositor thread.
+  const size_t kMappedMemoryReclaimLimit = max_bytes_pending_upload;
+
+  if (!context->Initialize(
           attributes,
           false /* bind generates resources */,
-          CAUSE_FOR_GPU_LAUNCH_WEBGRAPHICSCONTEXT3DCOMMANDBUFFERIMPL_INITIALIZE))
+          CAUSE_FOR_GPU_LAUNCH_WEBGRAPHICSCONTEXT3DCOMMANDBUFFERIMPL_INITIALIZE,
+          kDefaultCommandBufferSize,
+          kDefaultStartTransferBufferSize,
+          kDefaultMinTransferBufferSize,
+          kDefaultMaxTransferBufferSize,
+          kMappedMemoryReclaimLimit))
     return scoped_ptr<WebGraphicsContext3DCommandBufferImpl>();
   return context.Pass();
 }