1 /* Copyright 2018 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 #ifndef TENSORFLOW_CORE_COMMON_RUNTIME_BUF_RENDEZVOUS_H_ 16 #define TENSORFLOW_CORE_COMMON_RUNTIME_BUF_RENDEZVOUS_H_ 17 18 #include <functional> 19 #include <string> 20 21 #include "absl/container/flat_hash_map.h" 22 #include "absl/strings/string_view.h" 23 #include "tensorflow/core/framework/allocator.h" 24 #include "tensorflow/core/framework/cancellation.h" 25 #include "tensorflow/core/lib/core/status.h" 26 #include "tensorflow/core/platform/mutex.h" 27 28 namespace tensorflow { 29 class Device; 30 class DeviceContext; 31 class DeviceMgr; 32 class Tensor; 33 34 // EXPERIMENTAL: RDMA oriented producer/consumer rendezvous on a local 35 // Tensor value for which DMAHelper::CanUseDMA() is true, i.e. dense 36 // numeric types. Similar to Rendezvous but never owns a Ref on the 37 // tensor, instead it uses an explicit callback to the producer when 38 // the consumer side is finished with the value. This allows the 39 // producer to perform in-place updates on the source buffer or to take 40 // other actions that depend on knowing the consumer has passed a certain 41 // execution point. 42 class BufRendezvous { 43 public: BufRendezvous(uint64 step_id,const DeviceMgr * dev_mgr)44 explicit BufRendezvous(uint64 step_id, const DeviceMgr* dev_mgr) 45 : step_id_(step_id), dev_mgr_(dev_mgr) {} 46 47 virtual ~BufRendezvous(); 48 49 // Inform all waiting parties that this BufRendezvous is defunct because of 50 // an error Status interrupting the Step. 51 void StartAbort(const Status& s); 52 53 struct Hook; 54 // Provided by the consumer to be called when access to the buffer 55 // is available. If the Status arg is not OK, then hook will not 56 // be populated. Ownership of Hook passes to consumer with the 57 // callback. 58 typedef std::function<void(const Status&, Hook*)> ConsumerCallback; 59 // Provided by the producer to be called when the consumer has finished 60 // reading the buffer and will no longer access it. 61 typedef std::function<void(const Status&)> ProducerCallback; 62 63 struct Hook { 64 Device* prod_dev; 65 DeviceContext* prod_ctx; 66 const Tensor* prod_value; 67 AllocatorAttributes prod_attr; 68 ProducerCallback prod_cb; 69 ConsumerCallback cons_cb; 70 CancellationManager* cancellation_manager; 71 CancellationToken cancellation_token; HookHook72 explicit Hook(CancellationManager* cancellation_manager, 73 CancellationToken cancellation_token) 74 : prod_dev(nullptr), 75 prod_ctx(nullptr), 76 prod_value(nullptr), 77 prod_cb(nullptr), 78 cons_cb(nullptr), 79 cancellation_manager(cancellation_manager), 80 cancellation_token(cancellation_token) {} 81 string DebugString() const; 82 }; 83 84 // Called to advertise availability of a Tensor value corresponding 85 // to key. That value must stay valid until done is called. 86 // 87 // If a non-null cancellation manager is provided, this function registers a 88 // callback to delete the hook and invoke provider/consumer callbacks with 89 // cancelled error. 90 void ProvideBuf(const string& key, Device* dev, DeviceContext* dev_ctx, 91 const Tensor* v, const AllocatorAttributes& attr, 92 const ProducerCallback& done, 93 CancellationManager* cancellation_manager); 94 95 // Called to request access to a Tensor value corresponding to key. 96 // Consumer is provided with a Hook as soon as available. 97 // 98 // This function also checks that the current incarnation number of the 99 // `device` that produced this value matches the `incarnation` expected by the 100 // consumer, and invokes `done` with `FailedPrecondition` status and 101 // `nullptr` hook if it does not match. 102 // 103 // If a non-null cancellation manager is provided, this function registers a 104 // callback to delete the hook and invoke provider/consumer callbacks with 105 // cancelled error. 106 virtual void ConsumeBuf(const string& key, const string& device, 107 const uint64 incarnation, 108 const ConsumerCallback& done, 109 CancellationManager* cancellation_manager); 110 111 // Cancel the rendezvous entry corresponding to `key`. Triggered by the 112 // cancellation manager. No-op if the rendezvous was already successful. 113 void CancelHook(const string& key); 114 115 // Consumer must call this function when it's done reading the Hook provided 116 // by the ConsumerCallback. This function will invoke the producer callback 117 // and then delete h. 118 static void DoneWithHook(Hook* h); 119 120 // Write the current contents of the table to the INFO log. 121 void LogContents(); 122 123 protected: 124 const uint64 step_id_; 125 const DeviceMgr* const dev_mgr_; // Not owned. 126 mutex mu_; 127 Status status_ TF_GUARDED_BY(mu_); 128 typedef absl::flat_hash_map<string, Hook*> HookTable; 129 HookTable hook_table_ TF_GUARDED_BY(mu_); 130 131 void PurgeTable(const Status& s, HookTable* table); 132 }; 133 } // namespace tensorflow 134 #endif // TENSORFLOW_CORE_COMMON_RUNTIME_BUF_RENDEZVOUS_H_ 135