Ensure that GpuScheduler invokes fence tasks even if client is not flushing.

Review URL: http://codereview.chromium.org/8495038

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@113535 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 31 insertions, 8 deletions

diff --git a/content/common/gpu/gpu_channel.cc b/content/common/gpu/gpu_channel.cc
index 27eb490..e8cc269 100644
--- a/content/common/gpu/gpu_channel.cc
+++ b/content/common/gpu/gpu_channel.cc
@@ -26,6 +26,10 @@
 #include "ipc/ipc_channel_posix.h"
 #endif
 
+namespace {
+const int64 kHandleMoreWorkPeriod = 1;
+}
+
 GpuChannel::GpuChannel(GpuChannelManager* gpu_channel_manager,
                        GpuWatchdog* watchdog,
                        int renderer_id,
@@ -154,7 +158,7 @@ void GpuChannel::OnScheduled() {
   // Post a task to handle any deferred messages. The deferred message queue is
   // not emptied here, which ensures that OnMessageReceived will continue to
   // defer newly received messages until the ones in the queue have all been
-  // handled by HandleDeferredMessages. HandleDeferredMessages is invoked as a
+  // handled by HandleMessage. HandleMessage is invoked as a
   // task to prevent reentrancy.
   MessageLoop::current()->PostTask(
       FROM_HERE,
@@ -256,18 +260,28 @@ void GpuChannel::HandleMessage() {
         Send(reply);
       }
     } else {
-      // If the channel becomes unscheduled as a result of handling the message,
-      // synthesize an IPC message to flush the command buffer that became
-      // unscheduled.
+      // If the channel becomes unscheduled as a result of handling the message
+      // or has more work to do, synthesize an IPC message to flush the command
+      // buffer that became unscheduled.
+      bool has_more_work = false;
       for (StubMap::Iterator<GpuCommandBufferStub> it(&stubs_);
            !it.IsAtEnd();
            it.Advance()) {
         GpuCommandBufferStub* stub = it.GetCurrentValue();
-        if (!stub->IsScheduled()) {
+
+        if (!stub->IsScheduled() || stub->HasMoreWork()) {
+          has_more_work = true;
           deferred_messages_.push_front(new GpuCommandBufferMsg_Rescheduled(
               stub->route_id()));
         }
       }
+
+      if (has_more_work) {
+        MessageLoop::current()->PostDelayedTask(
+            FROM_HERE,
+            base::Bind(&GpuChannel::HandleMessage, weak_factory_.GetWeakPtr()),
+            kHandleMoreWorkPeriod);
+      }
     }
   }
 
diff --git a/content/common/gpu/gpu_command_buffer_stub.cc b/content/common/gpu/gpu_command_buffer_stub.cc
index af478e0..ff2ab82 100644
--- a/content/common/gpu/gpu_command_buffer_stub.cc
+++ b/content/common/gpu/gpu_command_buffer_stub.cc
@@ -123,6 +123,10 @@ bool GpuCommandBufferStub::IsScheduled() {
   return !scheduler_.get() || scheduler_->IsScheduled();
 }
 
+bool GpuCommandBufferStub::HasMoreWork() {
+  return scheduler_.get() && scheduler_->HasMoreWork();
+}
+
 void GpuCommandBufferStub::SetSwapInterval() {
 #if !defined(OS_MACOSX) && !defined(UI_COMPOSITOR_IMAGE_TRANSPORT)
   // Set up swap interval for onscreen contexts.
@@ -360,10 +364,12 @@ void GpuCommandBufferStub::OnAsyncFlush(int32 put_offset,
 }
 
 void GpuCommandBufferStub::OnRescheduled() {
-  gpu::CommandBuffer::State state = command_buffer_->GetLastState();
-  command_buffer_->Flush(state.put_offset);
+  gpu::CommandBuffer::State pre_state = command_buffer_->GetLastState();
+  command_buffer_->Flush(pre_state.put_offset);
+  gpu::CommandBuffer::State post_state = command_buffer_->GetLastState();
 
-  ReportState();
+  if (pre_state.get_offset != post_state.get_offset)
+    ReportState();
 }
 
 void GpuCommandBufferStub::OnCreateTransferBuffer(int32 size,
diff --git a/content/common/gpu/gpu_command_buffer_stub.h b/content/common/gpu/gpu_command_buffer_stub.h
index f581593..50e2b23 100644
--- a/content/common/gpu/gpu_command_buffer_stub.h
+++ b/content/common/gpu/gpu_command_buffer_stub.h
@@ -65,6 +65,9 @@ class GpuCommandBufferStub
   // Whether this command buffer can currently handle IPC messages.
   bool IsScheduled();
 
+  // Whether this command buffer needs to be polled again in the future.
+  bool HasMoreWork();
+
   // Set the swap interval according to the command line.
   void SetSwapInterval();