1 #include "benchmark/benchmark.h" 2 3 #include <map> 4 5 namespace { 6 7 std::map<int, int> ConstructRandomMap(int size) { 8 std::map<int, int> m; 9 for (int i = 0; i < size; ++i) { 10 m.insert(std::make_pair(rand() % size, rand() % size)); 11 } 12 return m; 13 } 14 15 } // namespace 16 17 // Basic version. 18 static void BM_MapLookup(benchmark::State& state) { 19 const int size = state.range_x(); 20 while (state.KeepRunning()) { 21 state.PauseTiming(); 22 std::map<int, int> m = ConstructRandomMap(size); 23 state.ResumeTiming(); 24 for (int i = 0; i < size; ++i) { 25 benchmark::DoNotOptimize(m.find(rand() % size)); 26 } 27 } 28 state.SetItemsProcessed(state.iterations() * size); 29 } 30 BENCHMARK(BM_MapLookup)->Range(1 << 3, 1 << 12); 31 32 // Using fixtures. 33 class MapFixture : public ::benchmark::Fixture { 34 public: 35 void SetUp(const ::benchmark::State& st) { 36 m = ConstructRandomMap(st.range_x()); 37 } 38 39 void TearDown() { 40 m.clear(); 41 } 42 43 std::map<int, int> m; 44 }; 45 46 BENCHMARK_DEFINE_F(MapFixture, Lookup)(benchmark::State& state) { 47 const int size = state.range_x(); 48 while (state.KeepRunning()) { 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
