select_op.cc 14.5 KB
Newer Older
T
Thuan Nguyen 已提交
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
/* Copyright (c) 2016 PaddlePaddle Authors. All Rights Reserved.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License. */

#include <memory>
16
#include <thread>  // NOLINT
T
Thuan Nguyen 已提交
17 18 19 20 21 22 23
#include <vector>
#include "paddle/fluid/framework/channel.h"
#include "paddle/fluid/framework/executor.h"
#include "paddle/fluid/framework/lod_tensor.h"
#include "paddle/fluid/framework/op_registry.h"
#include "paddle/fluid/operators/concurrency/channel_util.h"

24 25
#include <boost/tokenizer.hpp>

T
Thuan Nguyen 已提交
26 27 28 29 30
namespace paddle {
namespace operators {

static constexpr char kX[] = "X";
static constexpr char kCaseToExecute[] = "case_to_execute";
31
static constexpr char kOutputs[] = "Out";
T
Thuan Nguyen 已提交
32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257

static constexpr char kCases[] = "cases";
static constexpr char kCasesBlock[] = "sub_block";

class SelectOp : public framework::OperatorBase {
 public:
  SelectOp(const std::string &type, const framework::VariableNameMap &inputs,
           const framework::VariableNameMap &outputs,
           const framework::AttributeMap &attrs)
      : framework::OperatorBase(type, inputs, outputs, attrs) {}

 private:
  enum class SelectOpCaseType {
    DEFAULT = 0,
    SEND = 1,
    RECEIVE = 2,
  };

  struct SelectOpCase {
    int caseIndex;
    SelectOpCaseType caseType;
    std::string channelName;
    std::string varName;

    SelectOpCase() {}

    SelectOpCase(int caseIndex, SelectOpCaseType caseType,
                 std::string channelName, std::string varName)
        : caseIndex(caseIndex),
          caseType(caseType),
          channelName(channelName),
          varName(varName) {}
  };

  void RunImpl(const framework::Scope &scope,
               const platform::Place &dev_place) const override {
    std::vector<std::string> casesConfigs =
        Attr<std::vector<std::string>>(kCases);

    framework::BlockDesc *casesBlock =
        Attr<framework::BlockDesc *>(kCasesBlock);

    framework::Scope &casesBlockScope = scope.NewScope();

    std::string caseToExecuteVarName = Input(kCaseToExecute);
    framework::Variable *caseToExecuteVar =
        casesBlockScope.FindVar(caseToExecuteVarName);

    // Construct cases from "conditional_block_op"(s) in the casesBlock
    std::vector<std::shared_ptr<SelectOpCase>> cases =
        ParseAndShuffleCases(&casesConfigs);

    // Get all unique channels involved in select
    std::set<framework::ChannelHolder *> channelsSet;
    for (auto c : cases) {
      if (!c->channelName.empty()) {
        auto channelVar = scope.FindVar(c->channelName);
        framework::ChannelHolder *ch =
            channelVar->GetMutable<framework::ChannelHolder>();

        if (channelsSet.find(ch) == channelsSet.end()) {
          channelsSet.insert(ch);
        }
      }
    }

    // Order all channels by their pointer address
    std::vector<framework::ChannelHolder *> channels(channelsSet.begin(),
                                                     channelsSet.end());
    std::sort(channels.begin(), channels.end());

    // Poll all cases
    int32_t caseToExecute = pollCases(&scope, &cases, channels);

    // At this point, the case to execute has already been determined,
    // so we can proceed with executing the cases block
    framework::LoDTensor *caseToExecuteTensor =
        caseToExecuteVar->GetMutable<framework::LoDTensor>();
    caseToExecuteTensor->data<int32_t>()[0] = caseToExecute;

    // Execute the cases block, only one case will be executed since we set the
    // case_to_execute value to the index of the case we want to execute
    framework::Executor executor(dev_place);
    framework::ProgramDesc *program = casesBlock->Program();
    executor.Run(*program, &casesBlockScope, casesBlock->ID(),
                 false /*create_local_scope*/);
  }

  /**
   * Goes through all operators in the casesConfigs and processes
   * "conditional_block" operators.  These operators are mapped to our
   * SelectOpCase objects.  We randomize the case orders, and set the
   * default case (if any exists) as the last case)
   * @param casesBlock
   * @return
   */
  std::vector<std::shared_ptr<SelectOpCase>> ParseAndShuffleCases(
      std::vector<std::string> *casesConfigs) const {
    std::vector<std::shared_ptr<SelectOpCase>> cases;
    std::shared_ptr<SelectOpCase> defaultCase;

    if (casesConfigs != nullptr) {
      boost::char_delimiters_separator<char> sep(false, ",", "");
      for (std::vector<std::string>::iterator itr = casesConfigs->begin();
           itr < casesConfigs->end(); ++itr) {
        std::string caseConfig = *itr;
        boost::tokenizer<> tokens(caseConfig, sep);

        boost::tokenizer<>::iterator tok_iter = tokens.begin();
        PADDLE_ENFORCE(tok_iter != tokens.end(), "Cannot get case index");
        std::string caseIndexString = *tok_iter;
        int caseIndex = std::stoi(caseIndexString);

        ++tok_iter;
        PADDLE_ENFORCE(tok_iter != tokens.end(), "Cannot get case type");
        std::string caseTypeString = *tok_iter;
        SelectOpCaseType caseType = (SelectOpCaseType)std::stoi(caseTypeString);

        std::string caseChannel;
        std::string caseChannelVar;

        ++tok_iter;
        if (caseType != SelectOpCaseType::DEFAULT) {
          PADDLE_ENFORCE(tok_iter != tokens.end(), "Cannot get case channel");
          caseChannel = *tok_iter;

          ++tok_iter;
          PADDLE_ENFORCE(tok_iter != tokens.end(),
                         "Cannot get case channel variable");
          caseChannelVar = *tok_iter;
        }

        auto c = std::make_shared<SelectOpCase>(caseIndex, caseType,
                                                caseChannel, caseChannelVar);

        if (caseType == SelectOpCaseType::DEFAULT) {
          PADDLE_ENFORCE(defaultCase == nullptr,
                         "Select can only contain one default case.");
          defaultCase = c;
        } else {
          cases.push_back(c);
        }
      }
    }

    // Randomly sort cases, with default case being last
    std::random_shuffle(cases.begin(), cases.end());
    if (defaultCase != nullptr) {
      cases.push_back(defaultCase);
    }

    return cases;
  }

  /**
   * This method will recursively poll the cases and determines if any case
   * condition is true.
   * If none of the cases conditions are true (and there is no default case),
   * then block
   * the thread.  The thread may be woken up by a channel operation, at which
   * point we
   * execute the case.
   * @param scope
   * @param cases
   * @param channels
   * @return
   */
  int32_t pollCases(const framework::Scope *scope,
                    std::vector<std::shared_ptr<SelectOpCase>> *cases,
                    std::vector<framework::ChannelHolder *> channels) const {
    // Lock all involved channels
    lockChannels(channels);

    std::atomic<int> caseToExecute(-1);

    std::vector<std::shared_ptr<SelectOpCase>>::iterator it = cases->begin();
    while (it != cases->end()) {
      std::shared_ptr<SelectOpCase> c = *it;

      auto chVar = scope->FindVar(c->channelName);
      framework::ChannelHolder *ch =
          chVar->GetMutable<framework::ChannelHolder>();

      switch (c->caseType) {
        case SelectOpCaseType::SEND:
          PADDLE_ENFORCE(!ch->IsClosed(), "Cannot send to a closed channel");
          if (ch->CanSend()) {
            // We can send to channel directly, send the data to channel
            // and execute case
            auto chVar = scope->FindVar(c->varName);
            concurrency::ChannelSend(ch, chVar);
            caseToExecute = c->caseIndex;
          }
          break;
        case SelectOpCaseType::RECEIVE:
          if (ch->CanReceive()) {
            // We can receive from channel directly, send the data to channel
            // and execute case
            auto chVar = scope->FindVar(c->varName);
            concurrency::ChannelReceive(ch, chVar);
            caseToExecute = c->caseIndex;
          }
          break;
        case SelectOpCaseType::DEFAULT:
          caseToExecute = c->caseIndex;
          break;
      }

      if (caseToExecute != -1) {
        // We found a case to execute, stop looking at other case statements
        break;
      }

      ++it;
    }

    if (caseToExecute == -1) {
      // None of the cases are eligible to execute, enqueue current thread
      // into all the sending/receiving queue of each involved channel
      std::atomic<bool> completed(false);
      std::recursive_mutex mutex;
      std::unique_lock<std::recursive_mutex> lock{mutex};
      // std::condition_variable_any selectCond;
      auto selectCond = std::make_shared<std::condition_variable_any>();

      std::recursive_mutex callbackMutex;
258 259
      pushThreadOnChannelQueues(scope, cases, selectCond, &caseToExecute,
                                &completed, &callbackMutex);
T
Thuan Nguyen 已提交
260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305

      // TODO(thuan): Atomically unlock all channels and sleep current thread
      unlockChannels(channels);
      selectCond->wait(lock, [&completed]() { return completed.load(); });

      // Select has been woken up by case operation
      lockChannels(channels);
      removeThreadOnChannelQueues(scope, cases);

      if (caseToExecute == -1) {
        // Recursively poll cases, since we were woken up by a channel close
        // TODO(thuan): Need to test if this is a valid case
        unlockChannels(channels);
        return pollCases(scope, cases, channels);
      }
    }

    // At this point, caseToExecute != -1, and we can proceed with executing
    // the case block
    unlockChannels(channels);

    return caseToExecute;
  }

  void lockChannels(std::vector<framework::ChannelHolder *> chs) const {
    std::vector<framework::ChannelHolder *>::iterator it = chs.begin();
    while (it != chs.end()) {
      framework::ChannelHolder *ch = *it;
      ch->Lock();
      ++it;
    }
  }

  void unlockChannels(std::vector<framework::ChannelHolder *> chs) const {
    std::vector<framework::ChannelHolder *>::reverse_iterator it = chs.rbegin();
    while (it != chs.rend()) {
      framework::ChannelHolder *ch = *it;
      ch->Unlock();
      ++it;
    }
  }

  void pushThreadOnChannelQueues(
      const framework::Scope *scope,
      std::vector<std::shared_ptr<SelectOpCase>> *cases,
      std::shared_ptr<std::condition_variable_any> rCond,
306 307
      std::atomic<int> *caseToExecute, std::atomic<bool> *completed,
      std::recursive_mutex *callbackMutex) const {
T
Thuan Nguyen 已提交
308 309 310 311 312 313 314 315 316 317 318
    std::vector<std::shared_ptr<SelectOpCase>>::iterator it = cases->begin();
    while (it != cases->end()) {
      std::shared_ptr<SelectOpCase> c = *it;

      auto chVar = scope->FindVar(c->channelName);
      framework::ChannelHolder *ch =
          chVar->GetMutable<framework::ChannelHolder>();

      std::function<bool(framework::ChannelAction channelAction)> cb =
          [&caseToExecute, &completed, &callbackMutex,
           c](framework::ChannelAction channelAction) {
319
            std::lock_guard<std::recursive_mutex> lock{*callbackMutex};
T
Thuan Nguyen 已提交
320 321

            bool canProcess = false;
322
            if (!(*completed)) {
T
Thuan Nguyen 已提交
323 324 325
              // If the channel wasn't closed, we set the caseToExecute index
              // as this current case
              if (channelAction != framework::ChannelAction::CLOSE) {
326
                *caseToExecute = c->caseIndex;
T
Thuan Nguyen 已提交
327 328
              }
              // This will allow our conditional variable to break out of wait
329
              *completed = true;
T
Thuan Nguyen 已提交
330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382
              canProcess = true;
            }

            return canProcess;
          };

      switch (c->caseType) {
        case SelectOpCaseType::SEND: {
          auto chOutputVar = scope->FindVar(c->varName);
          concurrency::ChannelAddToSendQ(ch, this, chOutputVar, rCond, cb);
          break;
        }
        case SelectOpCaseType::RECEIVE: {
          auto chOutputVar = scope->FindVar(c->varName);
          concurrency::ChannelAddToReceiveQ(ch, this, chOutputVar, rCond, cb);
          break;
        }
        default:
          break;
      }
      ++it;
    }
  }

  void removeThreadOnChannelQueues(
      const framework::Scope *scope,
      std::vector<std::shared_ptr<SelectOpCase>> *cases) const {
    std::vector<std::shared_ptr<SelectOpCase>>::iterator it = cases->begin();
    while (it != cases->end()) {
      std::shared_ptr<SelectOpCase> c = *it;

      auto chVar = scope->FindVar(c->channelName);
      framework::ChannelHolder *ch =
          chVar->GetMutable<framework::ChannelHolder>();
      switch (c->caseType) {
        case SelectOpCaseType::SEND: {
          ch->RemoveFromSendQ(this);
          break;
        }
        case SelectOpCaseType::RECEIVE: {
          ch->RemoveFromReceiveQ(this);
          break;
        }
        default:
          break;
      }
      ++it;
    }
  }
};

class SelectOpMaker : public framework::OpProtoAndCheckerMaker {
 public:
Y
Yu Yang 已提交
383
  void Make() override {
T
Thuan Nguyen 已提交
384 385 386 387 388 389 390 391
    AddInput(kX,
             "A set of variables, which are required by operators inside the "
             "cases of Select Op")
        .AsDuplicable();
    AddInput(kCaseToExecute,
             "(Int) The variable the sets the index of the case to execute, "
             "after evaluating the channels being sent to and received from")
        .AsDuplicable();
392 393 394 395
    AddOutput(kOutputs,
              "A set of variables, which will be assigned with values "
              "generated by the operators inside the cases of Select Op.")
        .AsDuplicable();
T
Thuan Nguyen 已提交
396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419
    AddAttr<std::vector<std::string>>(kCases,
                                      "(String vector) Serialized list of"
                                      "all cases in the select op. Each"
                                      "case is serialized as: "
                                      "'<index>,<type>,<channel>,<value>'"
                                      "where type is 0 for default, 1 for"
                                      "send, and 2 for receive"
                                      "No channel and values are needed for"
                                      "default cases.");
    AddAttr<framework::BlockDesc *>(kCasesBlock,
                                    "The cases block inside select_op");
    AddComment(R"DOC(
)DOC");
  }
};

// TODO(thuan): Implement Gradient Operator for SELECT_OP

}  // namespace operators
}  // namespace paddle

REGISTER_OPERATOR(select, paddle::operators::SelectOp,
                  paddle::framework::EmptyGradOpMaker,
                  paddle::operators::SelectOpMaker);