127 lines
4.7 KiB
C++
127 lines
4.7 KiB
C++
// Copyright 2017 The Abseil Authors.
|
|
//
|
|
// 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
|
|
//
|
|
// https://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 <cstdint>
|
|
#include <cstring>
|
|
|
|
#include "benchmark/benchmark.h"
|
|
#include "absl/algorithm/algorithm.h"
|
|
|
|
namespace {
|
|
|
|
// The range of sequence sizes to benchmark.
|
|
constexpr int kMinBenchmarkSize = 1024;
|
|
constexpr int kMaxBenchmarkSize = 8 * 1024 * 1024;
|
|
|
|
// A user-defined type for use in equality benchmarks. Note that we expect
|
|
// std::memcmp to win for this type: libstdc++'s std::equal only defers to
|
|
// memcmp for integral types. This is because it is not straightforward to
|
|
// guarantee that std::memcmp would produce a result "as-if" compared by
|
|
// operator== for other types (example gotchas: NaN floats, structs with
|
|
// padding).
|
|
struct EightBits {
|
|
explicit EightBits(int /* unused */) : data(0) {}
|
|
bool operator==(const EightBits& rhs) const { return data == rhs.data; }
|
|
uint8_t data;
|
|
};
|
|
|
|
template <typename T>
|
|
void BM_absl_equal_benchmark(benchmark::State& state) {
|
|
std::vector<T> xs(state.range(0), T(0));
|
|
std::vector<T> ys = xs;
|
|
while (state.KeepRunning()) {
|
|
const bool same = absl::equal(xs.begin(), xs.end(), ys.begin(), ys.end());
|
|
benchmark::DoNotOptimize(same);
|
|
}
|
|
}
|
|
|
|
template <typename T>
|
|
void BM_std_equal_benchmark(benchmark::State& state) {
|
|
std::vector<T> xs(state.range(0), T(0));
|
|
std::vector<T> ys = xs;
|
|
while (state.KeepRunning()) {
|
|
const bool same = std::equal(xs.begin(), xs.end(), ys.begin());
|
|
benchmark::DoNotOptimize(same);
|
|
}
|
|
}
|
|
|
|
template <typename T>
|
|
void BM_memcmp_benchmark(benchmark::State& state) {
|
|
std::vector<T> xs(state.range(0), T(0));
|
|
std::vector<T> ys = xs;
|
|
while (state.KeepRunning()) {
|
|
const bool same =
|
|
std::memcmp(xs.data(), ys.data(), xs.size() * sizeof(T)) == 0;
|
|
benchmark::DoNotOptimize(same);
|
|
}
|
|
}
|
|
|
|
// The expectation is that the compiler should be able to elide the equality
|
|
// comparison altogether for sufficiently simple types.
|
|
template <typename T>
|
|
void BM_absl_equal_self_benchmark(benchmark::State& state) {
|
|
std::vector<T> xs(state.range(0), T(0));
|
|
while (state.KeepRunning()) {
|
|
const bool same = absl::equal(xs.begin(), xs.end(), xs.begin(), xs.end());
|
|
benchmark::DoNotOptimize(same);
|
|
}
|
|
}
|
|
|
|
BENCHMARK_TEMPLATE(BM_absl_equal_benchmark, uint8_t)
|
|
->Range(kMinBenchmarkSize, kMaxBenchmarkSize);
|
|
BENCHMARK_TEMPLATE(BM_std_equal_benchmark, uint8_t)
|
|
->Range(kMinBenchmarkSize, kMaxBenchmarkSize);
|
|
BENCHMARK_TEMPLATE(BM_memcmp_benchmark, uint8_t)
|
|
->Range(kMinBenchmarkSize, kMaxBenchmarkSize);
|
|
BENCHMARK_TEMPLATE(BM_absl_equal_self_benchmark, uint8_t)
|
|
->Range(kMinBenchmarkSize, kMaxBenchmarkSize);
|
|
|
|
BENCHMARK_TEMPLATE(BM_absl_equal_benchmark, uint16_t)
|
|
->Range(kMinBenchmarkSize, kMaxBenchmarkSize);
|
|
BENCHMARK_TEMPLATE(BM_std_equal_benchmark, uint16_t)
|
|
->Range(kMinBenchmarkSize, kMaxBenchmarkSize);
|
|
BENCHMARK_TEMPLATE(BM_memcmp_benchmark, uint16_t)
|
|
->Range(kMinBenchmarkSize, kMaxBenchmarkSize);
|
|
BENCHMARK_TEMPLATE(BM_absl_equal_self_benchmark, uint16_t)
|
|
->Range(kMinBenchmarkSize, kMaxBenchmarkSize);
|
|
|
|
BENCHMARK_TEMPLATE(BM_absl_equal_benchmark, uint32_t)
|
|
->Range(kMinBenchmarkSize, kMaxBenchmarkSize);
|
|
BENCHMARK_TEMPLATE(BM_std_equal_benchmark, uint32_t)
|
|
->Range(kMinBenchmarkSize, kMaxBenchmarkSize);
|
|
BENCHMARK_TEMPLATE(BM_memcmp_benchmark, uint32_t)
|
|
->Range(kMinBenchmarkSize, kMaxBenchmarkSize);
|
|
BENCHMARK_TEMPLATE(BM_absl_equal_self_benchmark, uint32_t)
|
|
->Range(kMinBenchmarkSize, kMaxBenchmarkSize);
|
|
|
|
BENCHMARK_TEMPLATE(BM_absl_equal_benchmark, uint64_t)
|
|
->Range(kMinBenchmarkSize, kMaxBenchmarkSize);
|
|
BENCHMARK_TEMPLATE(BM_std_equal_benchmark, uint64_t)
|
|
->Range(kMinBenchmarkSize, kMaxBenchmarkSize);
|
|
BENCHMARK_TEMPLATE(BM_memcmp_benchmark, uint64_t)
|
|
->Range(kMinBenchmarkSize, kMaxBenchmarkSize);
|
|
BENCHMARK_TEMPLATE(BM_absl_equal_self_benchmark, uint64_t)
|
|
->Range(kMinBenchmarkSize, kMaxBenchmarkSize);
|
|
|
|
BENCHMARK_TEMPLATE(BM_absl_equal_benchmark, EightBits)
|
|
->Range(kMinBenchmarkSize, kMaxBenchmarkSize);
|
|
BENCHMARK_TEMPLATE(BM_std_equal_benchmark, EightBits)
|
|
->Range(kMinBenchmarkSize, kMaxBenchmarkSize);
|
|
BENCHMARK_TEMPLATE(BM_memcmp_benchmark, EightBits)
|
|
->Range(kMinBenchmarkSize, kMaxBenchmarkSize);
|
|
BENCHMARK_TEMPLATE(BM_absl_equal_self_benchmark, EightBits)
|
|
->Range(kMinBenchmarkSize, kMaxBenchmarkSize);
|
|
|
|
} // namespace
|