| 1 | #include <cstdlib> |
|---|---|
| 2 | #include <map> |
| 3 | |
| 4 | #include "benchmark/benchmark.h" |
| 5 | |
| 6 | namespace { |
| 7 | |
| 8 | std::map<int, int> ConstructRandomMap(int size) { |
| 9 | std::map<int, int> m; |
| 10 | for (int i = 0; i < size; ++i) { |
| 11 | m.insert(x: std::make_pair(x: std::rand() % size, y: std::rand() % size)); |
| 12 | } |
| 13 | return m; |
| 14 | } |
| 15 | |
| 16 | } // namespace |
| 17 | |
| 18 | // Basic version. |
| 19 | static void BM_MapLookup(benchmark::State& state) { |
| 20 | const int size = static_cast<int>(state.range(pos: 0)); |
| 21 | std::map<int, int> m; |
| 22 | for (auto _ : state) { |
| 23 | state.PauseTiming(); |
| 24 | m = ConstructRandomMap(size); |
| 25 | state.ResumeTiming(); |
| 26 | for (int i = 0; i < size; ++i) { |
| 27 | auto it = m.find(x: std::rand() % size); |
| 28 | benchmark::DoNotOptimize(value&: it); |
| 29 | } |
| 30 | } |
| 31 | state.SetItemsProcessed(state.iterations() * size); |
| 32 | } |
| 33 | BENCHMARK(BM_MapLookup)->Range(start: 1 << 3, limit: 1 << 12); |
| 34 | |
| 35 | // Using fixtures. |
| 36 | class MapFixture : public ::benchmark::Fixture { |
| 37 | public: |
| 38 | void SetUp(const ::benchmark::State& st) override { |
| 39 | m = ConstructRandomMap(size: static_cast<int>(st.range(pos: 0))); |
| 40 | } |
| 41 | |
| 42 | void TearDown(const ::benchmark::State&) override { m.clear(); } |
| 43 | |
| 44 | std::map<int, int> m; |
| 45 | }; |
| 46 | |
| 47 | BENCHMARK_DEFINE_F(MapFixture, Lookup)(benchmark::State& state) { |
| 48 | const int size = static_cast<int>(state.range(pos: 0)); |
| 49 | for (auto _ : state) { |
| 50 | for (int i = 0; i < size; ++i) { |
| 51 | auto it = m.find(x: std::rand() % size); |
| 52 | benchmark::DoNotOptimize(value&: it); |
| 53 | } |
| 54 | } |
| 55 | state.SetItemsProcessed(state.iterations() * size); |
| 56 | } |
| 57 | BENCHMARK_REGISTER_F(MapFixture, Lookup)->Range(start: 1 << 3, limit: 1 << 12); |
| 58 | |
| 59 | BENCHMARK_MAIN(); |
| 60 |