Benchmark Transform Reduce algo

benchmark_transform_reduce.cpp

#include <numeric>
#include <vector>
#include <execution>

const int N = 1000000;

std::vector<double> xs(N, 1.1);
std::vector<double> ys(N, 1.1);

double inner_product_1(const std::vector<double>& xs, const std::vector<double>& ys) {
  return std::inner_product(xs.cbegin(), xs.cend(), ys.cbegin(), 0);
}

template <class P>
double inner_product_2(P&& policy, const std::vector<double>& xs, const std::vector<double>& ys) {
  return std::transform_reduce(policy, xs.cbegin(), xs.cend(), ys.cbegin(), 0);
}

double inner_product_3(const std::vector<double>& xs, const std::vector<double>& ys) {
  return std::transform_reduce(xs.cbegin(), xs.cend(), ys.cbegin(), 0);
}

static void bench_inner_product_1(benchmark::State& state) {
  double total = 0;
  for (auto _ : state) {
    benchmark::DoNotOptimize(total += inner_product_1(xs, ys));
  }
}
BENCHMARK(bench_inner_product_1);

static void bench_inner_product_2(benchmark::State& state) {
  double total = 0;
  for (auto _ : state) {
    benchmark::DoNotOptimize(total += inner_product_2(std::execution::seq, xs, ys));
  }
}
BENCHMARK(bench_inner_product_2);

static void bench_inner_product_3(benchmark::State& state) {
  double total = 0;
  for (auto _ : state) {
    benchmark::DoNotOptimize(total += inner_product_2(std::execution::par, xs, ys));
  }
}
BENCHMARK(bench_inner_product_3);

static void bench_inner_product_4(benchmark::State& state) {
  double total = 0;
  for (auto _ : state) {
    benchmark::DoNotOptimize(total += inner_product_2(std::execution::par_unseq, xs, ys));
  }
}
BENCHMARK(bench_inner_product_4);

static void bench_inner_product_5(benchmark::State& state) {
  double total = 0;
  for (auto _ : state) {
    benchmark::DoNotOptimize(total += inner_product_2(std::execution::unseq, xs, ys));
  }
}
BENCHMARK(bench_inner_product_5);

static void bench_inner_product_6(benchmark::State& state) {
  double total = 0;
  for (auto _ : state) {
    benchmark::DoNotOptimize(total += inner_product_3(xs, ys));
  }
}
BENCHMARK(bench_inner_product_6);