multi_alu.cpp

// Copyright 2020 The Division Authors.
//
// 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
//
//      https://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.
// Author dietoad@gmail.com && firedtoad@gmail.com

#include <benchmark/benchmark.h>
#include <vector>

static void BM_SingleNoOptimize(benchmark::State &state)
{
    int32_t range = state.range(0);
    for (auto _ : state)
    {
        double sum = 0;
        for (int32_t n = 0; n < range; n++)
        {
            sum += n * 0.01;
            benchmark::DoNotOptimize(sum);
        }
        for (int64_t n = 0; n < range; n++)
        {
            sum += (n / 100.0);
            benchmark::DoNotOptimize(sum);
        }
        benchmark::DoNotOptimize(sum);
    }
}

static void BM_Single(benchmark::State &state)
{
    int32_t range = state.range(0);
    for (auto _ : state)
    {
        double sum = 0;
        for (int32_t n = 0; n < range; n++)
        {
            sum += n * 0.01;
        }
        for (int64_t n = 0; n < range; n++)
        {
            sum += n / 100.0;
        }
        benchmark::DoNotOptimize(sum);
    }
}

static void BM_Multi(benchmark::State &state)
{
    int64_t range = state.range(0);
    for (auto _ : state)
    {
        double sum = 0;
        for (int32_t n = 0; n < range; n++)
        {
            sum += n * 0.01;
            sum += n / 100.0;
        }
        benchmark::DoNotOptimize(sum);
    }
}
BENCHMARK(BM_SingleNoOptimize)->Range(1024 * 1024, 1024 * 1024);
BENCHMARK(BM_Single)->Range(1024 * 1024, 1024 * 1024);
BENCHMARK(BM_Multi)->Range(1024 * 1024, 1024 * 1024);

int main(int argc, char **argv)
{
    benchmark::Initialize(&argc, argv);
    benchmark::RunSpecifiedBenchmarks();
    return 0;
}