tests/cpp/engine/thread_local_test.cc

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.
 */

/*!
 * \file engine_thread_local_test.cc
 * \brief Tests thread safety and lifetime of thread local store
 */
#include <gtest/gtest.h>
#include <dmlc/logging.h>
#include <dmlc/thread_group.h>
#include <dmlc/omp.h>
#include <mxnet/c_api.h>
#include <mxnet/engine.h>
#include <mxnet/ndarray.h>
#include <dmlc/timer.h>
#include <ctime>
#include <cstdio>
#include <thread>
#include <chrono>
#include <vector>

struct A {
  std::vector<int> a;
};
int num_threads  = 10;
int num_elements = num_threads * 10;

static int ThreadSafetyTest(int num, std::vector<int>* tmp_inputs, std::vector<int*>* res) {
  A* ret = dmlc::ThreadLocalStore<A>::Get();
  for (size_t i = num * 10; i < num * 10 + 10; ++i) {
    (*tmp_inputs)[i] = i;
  }
  ret->a.clear();
  ret->a.reserve(10);
  for (size_t i = num * 10; i < num * 10 + 10; ++i) {
    ret->a.push_back((*tmp_inputs)[i]);
  }
  (*res)[num] = dmlc::BeginPtr(ret->a);
  return 0;
}

TEST(ThreadLocal, VerifyThreadSafety) {
  std::vector<int> tmp_inputs;
  tmp_inputs.resize(num_elements);
  std::vector<int*> outputs;
  outputs.resize(num_threads);
  auto func = [&](int num) { ThreadSafetyTest(num, &tmp_inputs, &outputs); };
  std::vector<std::thread> worker_threads(num_threads);
  int count = 0;
  for (auto&& i : worker_threads) {
    i = std::thread(func, count);
    count++;
  }
  for (auto&& i : worker_threads) {
    i.join();
  }

  for (size_t i = 0; i < num_elements; i++) {
    CHECK(outputs[i / 10][i % 10] == i);
  }
}