| #include <cstdlib> |
| #include <map> |
| |
| #include "benchmark/benchmark.h" |
| |
| namespace { |
| |
| std::map<int, int> ConstructRandomMap(int size) { |
| std::map<int, int> m; |
| for (int i = 0; i < size; ++i) { |
| m.insert(std::make_pair(std::rand() % size, std::rand() % size)); |
| } |
| return m; |
| } |
| |
| } // namespace |
| |
| // Basic version. |
| static void BM_MapLookup(benchmark::State& state) { |
| const int size = static_cast<int>(state.range(0)); |
| std::map<int, int> m; |
| for (auto _ : state) { |
| state.PauseTiming(); |
| m = ConstructRandomMap(size); |
| state.ResumeTiming(); |
| for (int i = 0; i < size; ++i) { |
| auto it = m.find(std::rand() % size); |
| benchmark::DoNotOptimize(it); |
| } |
| } |
| state.SetItemsProcessed(state.iterations() * size); |
| } |
| BENCHMARK(BM_MapLookup)->Range(1 << 3, 1 << 12); |
| |
| // Using fixtures. |
| class MapFixture : public ::benchmark::Fixture { |
| public: |
| void SetUp(const ::benchmark::State& st) override { |
| m = ConstructRandomMap(static_cast<int>(st.range(0))); |
| } |
| |
| void TearDown(const ::benchmark::State&) override { m.clear(); } |
| |
| std::map<int, int> m; |
| }; |
| |
| BENCHMARK_DEFINE_F(MapFixture, Lookup)(benchmark::State& state) { |
| const int size = static_cast<int>(state.range(0)); |
| for (auto _ : state) { |
| for (int i = 0; i < size; ++i) { |
| auto it = m.find(std::rand() % size); |
| benchmark::DoNotOptimize(it); |
| } |
| } |
| state.SetItemsProcessed(state.iterations() * size); |
| } |
| BENCHMARK_REGISTER_F(MapFixture, Lookup)->Range(1 << 3, 1 << 12); |
| |
| BENCHMARK_MAIN(); |