Cooperatively round robin GPU command buffers.

gpu/command_buffer/client/cmd_buffer_helper.h

 // Copyright (c) 2011 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 command buffer helper class.
 
 #ifndef GPU_COMMAND_BUFFER_CLIENT_CMD_BUFFER_HELPER_H_
 #define GPU_COMMAND_BUFFER_CLIENT_CMD_BUFFER_HELPER_H_
 
 #include <string.h>
+#include <time.h>
 
 #include "../common/logging.h"
 #include "../common/constants.h"
 #include "../common/cmd_buffer_common.h"
 #include "../common/command_buffer.h"
 
 namespace gpu {
 
 // Command buffer helper class. This class simplifies ring buffer management:
 // it will allocate the buffer, give it to the buffer interface, and let the
@@ skipping 59 matching lines @@
   // NOTE: This will call Flush if it needs to block.
   // Parameters:
   //   the value of the token to wait for.
   void WaitForToken(int32 token);
 
   // Inserts a yield command, signaling the scheduler that this is a good point
   // to update the state and schedule other command buffers. This is
   // particularly useful after inserting a token that will be waited on.
   void YieldScheduler();
 
-  // Waits for a certain amount of space to be available. Returns address
-  // of space.
+  // Called prior to each command being issued. Waits for a certain amount of
+  // space to be available. Returns address of space.
   CommandBufferEntry* GetSpace(uint32 entries);
 
   // Typed version of GetSpace. Gets enough room for the given type and returns
   // a reference to it.
   template <typename T>
   T& GetCmdSpace() {
     COMPILE_ASSERT(T::kArgFlags == cmd::kFixed, Cmd_kArgFlags_not_kFixed);
     uint32 space_needed = ComputeNumEntries(sizeof(T));
     void* data = GetSpace(space_needed);
     return *reinterpret_cast<T*>(data);
@@ skipping 127 matching lines @@
   CommandBuffer* command_buffer_;
   Buffer ring_buffer_;
   CommandBufferEntry *entries_;
   int32 total_entry_count_;  // the total number of entries
   int32 usable_entry_count_;  // the usable number (ie, minus space for jump)
   int32 token_;
   int32 last_token_read_;
   int32 get_;
   int32 put_;
   int32 last_put_sent_;
+  int commands_issued_;
+
+  // Using C runtime instead of base because this file cannot depend on base.
+  time_t last_flush_time_;
 
   friend class CommandBufferHelperTest;
   DISALLOW_COPY_AND_ASSIGN(CommandBufferHelper);
 };
 
 }  // namespace gpu
 
 #endif  // GPU_COMMAND_BUFFER_CLIENT_CMD_BUFFER_HELPER_H_