command_buffer: Batch command processing to reduce handler overheads.

gpu/command_buffer/service/cmd_parser.h

 // 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 command parser class.
 
 #ifndef GPU_COMMAND_BUFFER_SERVICE_CMD_PARSER_H_
 #define GPU_COMMAND_BUFFER_SERVICE_CMD_PARSER_H_
 
 #include "gpu/command_buffer/common/constants.h"
 #include "gpu/command_buffer/common/cmd_buffer_common.h"
 #include "gpu/gpu_export.h"
 
 namespace gpu {
 
 class AsyncAPIInterface;
 
 // Command parser class. This class parses commands from a shared memory
 // buffer, to implement some asynchronous RPC mechanism.
 class GPU_EXPORT CommandParser {
  public:
+  static const int kParseCommandsSlice = 20;
+
   explicit CommandParser(AsyncAPIInterface* handler);
 
   // Sets the buffer to read commands from.
   void SetBuffer(
       void* shm_address,
       size_t shm_size,
       ptrdiff_t offset,
       size_t size);
 
   // Gets the "get" pointer. The get pointer is an index into the command
@@ skipping 16 matching lines @@
 
   // Gets the "put" pointer. The put pointer is an index into the command
   // buffer considered as an array of CommandBufferEntry.
   CommandBufferOffset put() const { return put_; }
 
   // Checks whether there are commands to process.
   bool IsEmpty() const { return put_ == get_; }
 
   // Processes one command, updating the get pointer. This will return an error
   // if there are no commands in the buffer.
-  error::Error ProcessCommand();
+  error::Error ProcessCommands(int num_commands);
 
   // Processes all commands until get == put.
   error::Error ProcessAllCommands();
 
   // Reports an error.
   void ReportError(unsigned int command_id, error::Error result);
 
  private:
   CommandBufferOffset get_;
   CommandBufferOffset put_;
   CommandBufferEntry* buffer_;
   int32 entry_count_;
   AsyncAPIInterface* handler_;
 };
 
 // This class defines the interface for an asynchronous API handler, that
 // is responsible for de-multiplexing commands and their arguments.
 class AsyncAPIInterface {
  public:
   AsyncAPIInterface() {}
   virtual ~AsyncAPIInterface() {}
 
-  // Executes a command.
+  // Executes a single command.
   // Parameters:
   //    command: the command index.
   //    arg_count: the number of CommandBufferEntry arguments.
   //    cmd_data: the command data.
   // Returns:
   //   error::kNoError if no error was found, one of
   //   error::Error otherwise.
   virtual error::Error DoCommand(
       unsigned int command,
       unsigned int arg_count,
       const void* cmd_data) = 0;
 
+  // Executes multiple commands.
+  // Parameters:
+  //  todo...
+  virtual error::Error DoCommands(unsigned int num_commands,
+                                  const void* buffer,
+                                  int num_entries,
+                                  int* entries_processed);
+
   // Returns a name for a command. Useful for logging / debuging.
   virtual const char* GetCommandName(unsigned int command_id) const = 0;
 };
 
 }  // namespace gpu
 
 #endif  // GPU_COMMAND_BUFFER_SERVICE_CMD_PARSER_H_