thread_count.h

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/*
 * Copyright 2022 HEAVY.AI, Inc.
 *
 * 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.
 */

#pragma once

#include <algorithm>
#include <thread>

extern unsigned g_cpu_threads_override;
extern size_t g_max_import_threads;

inline int cpu_threads() {
  auto ov = g_cpu_threads_override;
  return (ov <= 0) ? std::max(2 * std::thread::hardware_concurrency(), 1U) : ov;
}

namespace import_export {
inline size_t num_import_threads(const int32_t copy_params_threads) {
  if (copy_params_threads > 0) {
    return static_cast<size_t>(copy_params_threads);
  }
  return std::min(static_cast<size_t>(std::thread::hardware_concurrency()),
                  g_max_import_threads);
}
}  // namespace import_export