void BM_async()

in benchmarks/summing_for_benchmark.cpp [160:192]

• 28 lines of code
• 5 McCabe index (conditional complexity)

void BM_async(benchmark::State& state) {
  const int num_threads = state.range(0);
  const int num_elements = state.range(1);
  int64_t sum = 0;
  int foo = 0;

  auto& input = getInputs(num_elements);
  for (auto UNUSED_VAR : state) {
    std::vector<int64_t> sums;
    ++foo;

    size_t chunkSize = (num_elements + num_threads - 1) / num_threads;

    std::vector<std::future<int64_t>> futures;

    for (int i = 0; i < num_elements; i += chunkSize) {
      futures.push_back(
          std::async([&input, foo, i, end = std::min<int>(num_elements, i + chunkSize)]() mutable {
            int64_t lsum = 0;
            for (; i != end; ++i) {
              lsum += input[i] * input[i] - 3 * foo * input[i];
            }
            return lsum;
          }));
    }
    sum = 0;
    for (auto& s : futures) {
      sum += s.get();
    }
  }

  checkResults(input, sum, foo);
}