1 /* Copyright 2017 The TensorFlow Authors. All Rights Reserved. 2 3 Licensed under the Apache License, Version 2.0 (the "License"); 4 you may not use this file except in compliance with the License. 5 You may obtain a copy of the License at 6 7 http://www.apache.org/licenses/LICENSE-2.0 8 9 Unless required by applicable law or agreed to in writing, software 10 distributed under the License is distributed on an "AS IS" BASIS, 11 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 See the License for the specific language governing permissions and 13 limitations under the License. 14 ==============================================================================*/ 15 16 #ifndef TENSORFLOW_COMPILER_XLA_SERVICE_CHANNEL_TRACKER_H_ 17 #define TENSORFLOW_COMPILER_XLA_SERVICE_CHANNEL_TRACKER_H_ 18 19 #include <map> 20 21 #include "tensorflow/compiler/xla/service/hlo_module.h" 22 #include "tensorflow/compiler/xla/service/session.pb.h" 23 #include "tensorflow/compiler/xla/service/user_computation.h" 24 #include "tensorflow/compiler/xla/service/versioned_computation_handle.h" 25 #include "tensorflow/compiler/xla/status.h" 26 #include "tensorflow/compiler/xla/statusor.h" 27 #include "tensorflow/compiler/xla/types.h" 28 #include "tensorflow/compiler/xla/xla_data.pb.h" 29 #include "tensorflow/core/lib/gtl/array_slice.h" 30 #include "tensorflow/core/platform/macros.h" 31 #include "tensorflow/core/platform/mutex.h" 32 #include "tensorflow/core/platform/thread_annotations.h" 33 #include "tensorflow/core/platform/types.h" 34 35 namespace xla { 36 37 // Tracks channels between computations in the XLA service. Channels 38 // are associated with a unique handle and can be resolved from the handle for 39 // later use. 40 // 41 // TODO(b/34027823): Destruct channels when all the associated computations that 42 // communicate via each channel are destructed. 43 class ChannelTracker { 44 public: 45 ChannelTracker(); 46 47 // A struct that keeps the current status of each channel. has_sender and 48 // receiver_count fields are initialized with false and 0 respectively when 49 // the struct is created and are updated by RegisterSend() and RegisterRecev() 50 // as Send or Recv instructions using the channel are requested. 51 struct Channel { 52 bool has_sender; 53 int64 receiver_count; 54 }; 55 56 // Creates a new Channel object and returns the corresponding 57 // ChannelHandle for it. 58 ChannelHandle NewChannel(); 59 60 // Informs that the given channel handle is used for a Send operation. 61 // Returns an error status if the handle is already used by another Send. 62 Status RegisterSend(const ChannelHandle& handle); 63 64 // Informs that the given channel handle is used for a Recv operation. 65 // Returns an error status if the handle is already used by another Recv. 66 Status RegisterRecv(const ChannelHandle& handle); 67 68 private: 69 // Bumps the next_channel_ number and returns the allocated number 70 // wrapped in a ChannelHandle. 71 ChannelHandle AllocateHandle() EXCLUSIVE_LOCKS_REQUIRED(channel_mutex_); 72 73 Status RegisterSendInternal(const ChannelHandle& handle) 74 EXCLUSIVE_LOCKS_REQUIRED(channel_mutex_); 75 76 Status RegisterRecvInternal(const ChannelHandle& handle) 77 EXCLUSIVE_LOCKS_REQUIRED(channel_mutex_); 78 79 // Guards the channel mapping. 80 tensorflow::mutex channel_mutex_; 81 82 // The next sequence number to assign to a channel. 83 int64 next_channel_ GUARDED_BY(channel_mutex_); 84 85 // Mapping from ChannelHandle value to the corresponding registered 86 // Channel object. 87 std::map<int64, Channel> opaque_to_channel_ GUARDED_BY(channel_mutex_); 88 89 TF_DISALLOW_COPY_AND_ASSIGN(ChannelTracker); 90 }; 91 92 } // namespace xla 93 94 #endif // TENSORFLOW_COMPILER_XLA_SERVICE_CHANNEL_TRACKER_H_ 95
