Disable automatic flushes on compositor contexts.

gpu/command_buffer/client/cmd_buffer_helper.cc

 // Copyright (c) 2012 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.
 
 // This file contains the implementation of the command buffer helper class.
 
 #include "../client/cmd_buffer_helper.h"
 #include "../common/command_buffer.h"
 #include "../common/trace_event.h"
 
@@ skipping 10 matching lines @@
       ring_buffer_size_(0),
       entries_(NULL),
       total_entry_count_(0),
       usable_entry_count_(0),
       token_(0),
       put_(0),
       last_put_sent_(0),
       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());
   }
   return context_lost_;
 }
 
 bool CommandBufferHelper::AllocateRingBuffer() {
   if (!usable()) {
     return false;
@@ skipping 190 matching lines @@
     }
   }
   // Force a flush if the buffer is getting half full, or even earlier if the
   // reader is known to be idle.
   int32 pending =
       (put_ + usable_entry_count_ - last_put_sent_) % usable_entry_count_;
   int32 limit = usable_entry_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
     // kernel to thrash between generating GPU commands and executing them.
     clock_t current_time = clock();
     if (current_time - last_flush_time_ > kFlushDelay * CLOCKS_PER_SEC)
       Flush();
 #endif
   }
 }
@@ skipping 15 matching lines @@
   }
   return space;
 }
 
 error::Error CommandBufferHelper::GetError() {
   CommandBuffer::State state = command_buffer_->GetState();
   return static_cast<error::Error>(state.error);
 }
 
 }  // namespace gpu