utils/benchmark/test/map_test.cc

   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(std::rand() % size, 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(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(std::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(static_cast<int>(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 = static_cast<int>(state.range(0));
  48   for (auto _ : state) {
  49     for (int i = 0; i < size; ++i) {
  50       benchmark::DoNotOptimize(m.find(std::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();