WebGraphicsContext3DCommandBufferImpl cleanup, Canvas2D thottling fix, GpuScheduler fix.

gpu/command_buffer/service/gpu_scheduler.cc

Index: gpu/command_buffer/service/gpu_scheduler.cc
diff --git a/gpu/command_buffer/service/gpu_scheduler.cc b/gpu/command_buffer/service/gpu_scheduler.cc
index 151ff9afd8d4978563ec1451d9eea368b8cf5d60..6a8f5eb1c2751da5bd4988a220742ccbfb4d21de 100644
--- a/gpu/command_buffer/service/gpu_scheduler.cc
+++ b/gpu/command_buffer/service/gpu_scheduler.cc
@@ -9,6 +9,7 @@
 #include "base/compiler_specific.h"
 #include "base/debug/trace_event.h"
 #include "base/message_loop.h"
+#include "base/time.h"
 #include "ui/gfx/gl/gl_context.h"
 #include "ui/gfx/gl/gl_bindings.h"
 #include "ui/gfx/gl/gl_surface.h"
@@ -136,6 +137,7 @@ const unsigned int kMaxOutstandingSwapBuffersCallsPerOnscreenContext = 1;
 #endif
 
 void GpuScheduler::PutChanged(bool sync) {
+  TRACE_EVENT0("gpu", "GpuScheduler:PutChanged");
   CommandBuffer::State state = command_buffer_->GetState();
   parser_->set_put(state.put_offset);
 
@@ -151,8 +153,11 @@ void GpuScheduler::ProcessCommands() {
   if (state.error != error::kNoError)
     return;
 
-  if (unscheduled_count_ > 0)
+  if (unscheduled_count_ > 0) {
+    TRACE_EVENT1("gpu", "EarlyOut_Unscheduled",
+                 "unscheduled_count_", unscheduled_count_);
     return;
+  }
 
   if (decoder_.get()) {
     if (!decoder_->MakeCurrent()) {
@@ -175,32 +180,43 @@ void GpuScheduler::ProcessCommands() {
   }
 #endif
 
+  base::TimeTicks start_time = base::TimeTicks::Now();

[apatrick_chromium, 2011/06/02 22:07:43]

Does this have sufficient precision to measure 2ms on all platforms?

[jbates, 2011/06/03 00:05:55]

Not guaranteed according to the TimeTicks::Now() documentation, but even in the
worst case where some platform has 15ms resolution, we have latches and other
yielding means to make sure we switch contexts when necessary.

Any worse than 1ms granularity should be rare though, since we haven't seen
anything like that in our development environment.

+  base::TimeDelta elapsed;
+  bool is_break = false;
   error::Error error = error::kNoError;
-  int commands_processed = 0;
-  while (commands_processed < commands_per_update_ &&
-         !parser_->IsEmpty()) {
-    error = parser_->ProcessCommand();
-
-    // TODO(piman): various classes duplicate various pieces of state, leading
-    // to needlessly complex update logic. It should be possible to simply share
-    // the state across all of them.
-    command_buffer_->SetGetOffset(static_cast<int32>(parser_->get()));
-
-    if (error == error::kWaiting || error == error::kYield) {
-      break;
-    } else if (error::IsError(error)) {
-      command_buffer_->SetParseError(error);
-      return;
+  do {
+    int commands_processed = 0;
+    while (commands_processed < commands_per_update_ &&
+           !parser_->IsEmpty()) {
+      error = parser_->ProcessCommand();
+
+      // TODO(piman): various classes duplicate various pieces of state, leading
+      // to needlessly complex update logic. It should be possible to simply
+      // share the state across all of them.
+      command_buffer_->SetGetOffset(static_cast<int32>(parser_->get()));
+
+      if (error == error::kWaiting || error == error::kYield) {
+        is_break = true;
+        break;
+      } else if (error::IsError(error)) {
+        command_buffer_->SetParseError(error);
+        return;
+      }
+
+      if (unscheduled_count_ > 0) {
+        is_break = true;
+        break;
+      }
+
+      ++commands_processed;
+      if (command_processed_callback_.get()) {
+        command_processed_callback_->Run();
+      }
     }
-
-    if (unscheduled_count_ > 0)
-      break;
-
-    ++commands_processed;
-    if (command_processed_callback_.get()) {
-      command_processed_callback_->Run();
-    }
-  }
+    elapsed = base::TimeTicks::Now() - start_time;
+  } while(!is_break &&
+          !parser_->IsEmpty() &&
+          elapsed.InMicroseconds() < 2000);

[apatrick_chromium, 2011/06/02 22:07:43]

Could be a constant.

[jbates, 2011/06/03 00:05:55]

Done.

 
   if (unscheduled_count_ == 0 &&
       error != error::kWaiting &&
@@ -210,6 +226,8 @@ void GpuScheduler::ProcessCommands() {
 }
 
 void GpuScheduler::SetScheduled(bool scheduled) {
+  TRACE_EVENT2("gpu", "GpuScheduler:SetScheduled", "scheduled", scheduled,
+               "unscheduled_count_", unscheduled_count_);
   if (scheduled) {
     --unscheduled_count_;
     DCHECK_GE(unscheduled_count_, 0);