1 #include "benchmark/benchmark.h" 2 3 #include <cstdlib> 4 #include <map> 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(std::make_pair(rand() % size, 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 = state.range(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 benchmark::DoNotOptimize(m.find(rand() % size)); 28 } 29 } 30 state.SetItemsProcessed(state.iterations() * size); 31 } 32 BENCHMARK(BM_MapLookup)->Range(1 << 3, 1 << 12); 33 34 // Using fixtures. 35 class MapFixture : public ::benchmark::Fixture { 36 public: 37 void SetUp(const ::benchmark::State& st) { 38 m = ConstructRandomMap(st.range(0)); 39 } 40 41 void TearDown(const ::benchmark::State&) { m.clear(); } 42 43 std::map<int, int> m; 44 }; 45 46 BENCHMARK_DEFINE_F(MapFixture, Lookup)(benchmark::State& state) { 47 const int size = state.range(0); 48 for (auto _ : state) { 49 for (int i = 0; i < size; ++i) { 50 benchmark::DoNotOptimize(m.find(rand() % size)); 51 } 52 } 53 state.SetItemsProcessed(state.iterations() * size); 54 } 55 BENCHMARK_REGISTER_F(MapFixture, Lookup)->Range(1 << 3, 1 << 12); 56 57 BENCHMARK_MAIN(); 58
