1 #include "benchmark/benchmark.h"
2
3 #include <cstdlib>
4 #include <map>
5
6 namespace {
7
ConstructRandomMap(int size)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.
BM_MapLookup(benchmark::State & state)19 static void BM_MapLookup(benchmark::State& state) {
20 const int size = state.range(0);
21 while (state.KeepRunning()) {
22 state.PauseTiming();
23 std::map<int, int> m = ConstructRandomMap(size);
24 state.ResumeTiming();
25 for (int i = 0; i < size; ++i) {
26 benchmark::DoNotOptimize(m.find(rand() % size));
27 }
28 }
29 state.SetItemsProcessed(state.iterations() * size);
30 }
31 BENCHMARK(BM_MapLookup)->Range(1 << 3, 1 << 12);
32
33 // Using fixtures.
34 class MapFixture : public ::benchmark::Fixture {
35 public:
SetUp(const::benchmark::State & st)36 void SetUp(const ::benchmark::State& st) {
37 m = ConstructRandomMap(st.range(0));
38 }
39
TearDown(const::benchmark::State &)40 void TearDown(const ::benchmark::State&) { m.clear(); }
41
42 std::map<int, int> m;
43 };
44
BENCHMARK_DEFINE_F(MapFixture,Lookup)45 BENCHMARK_DEFINE_F(MapFixture, Lookup)(benchmark::State& state) {
46 const int size = state.range(0);
47 while (state.KeepRunning()) {
48 for (int i = 0; i < size; ++i) {
49 benchmark::DoNotOptimize(m.find(rand() % size));
50 }
51 }
52 state.SetItemsProcessed(state.iterations() * size);
53 }
54 BENCHMARK_REGISTER_F(MapFixture, Lookup)->Range(1 << 3, 1 << 12);
55
56 BENCHMARK_MAIN()
57