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25acf220a4
Recently the library added a new ranged-for variant of the KeepRunning loop that is much faster. For this reason it should be preferred in all new code. Because a library, its documentation, and its tests should all embody the best practices of using the library, this patch changes all but a few usages of KeepRunning() into for (auto _ : state). The remaining usages in the tests and documentation persist only to document and test behavior that is different between the two formulations. Also note that because the range-for loop requires C++11, the KeepRunning variant has not been deprecated at this time.
57 lines
1.3 KiB
C++
57 lines
1.3 KiB
C++
#include "benchmark/benchmark.h"
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#include <cstdlib>
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#include <map>
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namespace {
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std::map<int, int> ConstructRandomMap(int size) {
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std::map<int, int> m;
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for (int i = 0; i < size; ++i) {
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m.insert(std::make_pair(rand() % size, rand() % size));
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}
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return m;
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}
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} // namespace
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// Basic version.
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static void BM_MapLookup(benchmark::State& state) {
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const int size = state.range(0);
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for (auto _ : state) {
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state.PauseTiming();
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std::map<int, int> m = ConstructRandomMap(size);
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state.ResumeTiming();
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for (int i = 0; i < size; ++i) {
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benchmark::DoNotOptimize(m.find(rand() % size));
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}
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}
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state.SetItemsProcessed(state.iterations() * size);
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}
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BENCHMARK(BM_MapLookup)->Range(1 << 3, 1 << 12);
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// Using fixtures.
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class MapFixture : public ::benchmark::Fixture {
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public:
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void SetUp(const ::benchmark::State& st) {
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m = ConstructRandomMap(st.range(0));
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}
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void TearDown(const ::benchmark::State&) { m.clear(); }
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std::map<int, int> m;
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};
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BENCHMARK_DEFINE_F(MapFixture, Lookup)(benchmark::State& state) {
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const int size = state.range(0);
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for (auto _ : state) {
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for (int i = 0; i < size; ++i) {
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benchmark::DoNotOptimize(m.find(rand() % size));
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}
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}
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state.SetItemsProcessed(state.iterations() * size);
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}
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BENCHMARK_REGISTER_F(MapFixture, Lookup)->Range(1 << 3, 1 << 12);
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BENCHMARK_MAIN()
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