Files
filament/libs/utils/benchmark/benchmark_binary_search.cpp
Mathias Agopian 718e7ab064 remove a bunch of <functional> includes
This forces us to use an explicit hash class in a few place, but it
is cleaner.

remove utils::lower_bound and utils::upper_bound, which were not used.
2022-06-03 08:35:57 -07:00

98 lines
2.8 KiB
C++

/*
* Copyright (C) 2018 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "PerformanceCounters.h"
#include <utils/compiler.h>
#include <benchmark/benchmark.h>
#include <random>
#include <vector>
using namespace utils;
class BinarySearch : public benchmark::Fixture {
public:
BinarySearch();
~BinarySearch() override;
protected:
using value_type = uint64_t;
std::vector<value_type> data;
std::default_random_engine gen{123};
std::uniform_int_distribution<value_type> nd;
std::vector<value_type> prepareItems(size_t size);
};
BinarySearch::BinarySearch() {
data.resize(2<<20);
std::generate(data.begin(), data.end(), [&](){ return nd(gen); });
std::sort(data.begin(), data.end());
}
BinarySearch::~BinarySearch() = default;
UTILS_NOINLINE
std::vector<BinarySearch::value_type> BinarySearch::prepareItems(size_t size) {
auto first = data.begin();
auto last = data.begin() + size;
std::vector<value_type> indices(last - first);
std::copy(first, last, indices.begin());
std::default_random_engine gen{123};
std::shuffle(indices.begin(), indices.end(), gen);
return indices;
}
BENCHMARK_DEFINE_F(BinarySearch, linearSearch)(benchmark::State& state) {
auto first = data.begin();
auto last = data.begin() + state.range(0);
std::vector<value_type> indices = prepareItems(state.range(0));
value_type const* ip = indices.data();
size_t i = 0;
{
PerformanceCounters pc(state);
for (auto _ : state) {
auto item = ip[i++ % state.range(0)];
auto const& pos = std::find(first, last, item);
benchmark::DoNotOptimize(pos);
}
}
}
BENCHMARK_DEFINE_F(BinarySearch, stdLowerBound)(benchmark::State& state) {
auto first = data.begin();
auto last = data.begin() + state.range(0);
std::vector<value_type> indices = prepareItems(state.range(0));
value_type const* ip = indices.data();
size_t i = 0;
{
PerformanceCounters pc(state);
for (auto _ : state) {
auto item = ip[i++ % state.range(0)];
auto const& pos = std::lower_bound(first, last, item);
benchmark::DoNotOptimize(pos);
}
}
}
BENCHMARK_REGISTER_F(BinarySearch, linearSearch)->Range(2, 1<<20);
BENCHMARK_REGISTER_F(BinarySearch, stdLowerBound)->Range(2, 1<<20);