/*
 * Copyright (c) Facebook, Inc. and its affiliates.
 *
 * 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 <folly/system/HardwareConcurrency.h>

#include <thread>

#include <folly/portability/Sched.h>

namespace folly {

unsigned int hardware_concurrency() noexcept {
#if defined(__linux__) && !defined(__ANDROID__)
  cpu_set_t cpuset;
  if (!sched_getaffinity(0, sizeof(cpuset), &cpuset)) {
    auto count = CPU_COUNT(&cpuset);
    if (count != 0) {
      return count;
    }
  }
#endif

  return std::thread::hardware_concurrency();
}

} // namespace folly
