721d1a009e
Like some of the atomic_wait benchmarks, it is very expensive and only intended for A/B comparisons when actively investigating.
49 lines
1.6 KiB
C++
49 lines
1.6 KiB
C++
//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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// UNSUPPORTED: c++03, c++11, c++14
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// This benchmark is very expensive and we don't want to run it on a regular basis,
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// only to ensure the code doesn't rot.
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// REQUIRES: enable-benchmarks=dry-run
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// This benchmark compares the performance of std::mutex and std::shared_mutex in contended scenarios.
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// it's meant to establish a baseline overhead for std::shared_mutex and std::mutex, and to help inform decisions about
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// which mutex to use when selecting a mutex type for a given use case.
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#include <atomic>
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#include <mutex>
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#include <numeric>
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#include <shared_mutex>
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#include <thread>
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#include "benchmark/benchmark.h"
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int global_value = 42;
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std::mutex m;
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std::shared_mutex sm;
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static void BM_shared_mutex(benchmark::State& state) {
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for (auto _ : state) {
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std::shared_lock<std::shared_mutex> lock(sm);
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benchmark::DoNotOptimize(global_value);
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}
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}
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static void BM_mutex(benchmark::State& state) {
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for (auto _ : state) {
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std::lock_guard<std::mutex> lock(m);
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benchmark::DoNotOptimize(global_value);
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}
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}
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BENCHMARK(BM_shared_mutex)->Threads(1)->Threads(2)->Threads(4)->Threads(8)->Threads(32);
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BENCHMARK(BM_mutex)->Threads(1)->Threads(2)->Threads(4)->Threads(8)->Threads(32);
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BENCHMARK_MAIN();
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