Disable automatic flushes on compositor contexts.

The compositor contexts handle flushes themselves, so they don't need the automatic flushes, which can hurt performance.

BUG=152393


Review URL: https://chromiumcodereview.appspot.com/11099029

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@162434 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 13 insertions, 2 deletions

diff --git a/gpu/command_buffer/client/cmd_buffer_helper.cc b/gpu/command_buffer/client/cmd_buffer_helper.cc
index d556b5e..54df89e 100644
--- a/gpu/command_buffer/client/cmd_buffer_helper.cc
+++ b/gpu/command_buffer/client/cmd_buffer_helper.cc
@@ -28,9 +28,14 @@ CommandBufferHelper::CommandBufferHelper(CommandBuffer* command_buffer)
       commands_issued_(0),
       usable_(true),
       context_lost_(false),
+      flush_automatically_(true),
       last_flush_time_(0) {
 }
 
+void CommandBufferHelper::SetAutomaticFlushes(bool enabled) {
+  flush_automatically_ = enabled;
+}
+
 bool CommandBufferHelper::IsContextLost() {
   if (!context_lost_) {
     context_lost_ = error::IsError(command_buffer()->GetLastError());
@@ -241,8 +246,9 @@ void CommandBufferHelper::WaitForAvailableEntries(int32 count) {
       ((get_offset() == last_put_sent_) ? 16 : 2);
   if (pending > limit) {
     Flush();
-  } else if (commands_issued_ % kCommandsPerFlushCheck == 0) {
-#if !defined(OS_ANDROID) && !defined(OS_CHROMEOS)
+  } else if (flush_automatically_ &&
+             (commands_issued_ % kCommandsPerFlushCheck == 0)) {
+#if !defined(OS_ANDROID)
     // Allow this command buffer to be pre-empted by another if a "reasonable"
     // amount of work has been done. On highend machines, this reduces the
     // latency of GPU commands. However, on Android, this can cause the
diff --git a/gpu/command_buffer/client/cmd_buffer_helper.h b/gpu/command_buffer/client/cmd_buffer_helper.h
index 9922794..8e7cd78 100644
--- a/gpu/command_buffer/client/cmd_buffer_helper.h
+++ b/gpu/command_buffer/client/cmd_buffer_helper.h
@@ -44,6 +44,10 @@ class GPU_EXPORT CommandBufferHelper {
   //       buffer.
   bool Initialize(int32 ring_buffer_size);
 
+  // Sets whether the command buffer should automatically flush periodically
+  // to try to increase performance. Defaults to true.
+  void SetAutomaticFlushes(bool enabled);
+
   // True if the context is lost.
   bool IsContextLost();
 
@@ -292,6 +296,7 @@ class GPU_EXPORT CommandBufferHelper {
   int commands_issued_;
   bool usable_;
   bool context_lost_;
+  bool flush_automatically_;
 
   // Using C runtime instead of base because this file cannot depend on base.
   clock_t last_flush_time_;