core/src/engine/mutex_benchmark.cpp

#include <benchmark/benchmark.h>
 
#include <atomic>
#include <cstddef>
#include <mutex>
#include <thread>
#include <vector>
 
#include <userver/concurrent/impl/interference_shield.hpp>
#include <userver/engine/async.hpp>
#include <userver/engine/mutex.hpp>
#include <userver/engine/run_standalone.hpp>
#include <userver/engine/single_waiting_task_mutex.hpp>
#include <userver/utils/rand.hpp>
#include <utils/impl/parallelize_benchmark.hpp>
 
USERVER_NAMESPACE_BEGIN
 
namespace {

 
template <typename Mutex>
void GenericLock(benchmark::State& state) {
    constexpr std::size_t kMutexCount = 256;
    std::size_t i = 0;
    Mutex mutexes[kMutexCount];
 
    for ([[maybe_unused]] auto _ : state) {
        mutexes[i].lock();
 
        if (++i == kMutexCount) {
            state.PauseTiming();
            i = 0;
            for (auto& m : mutexes) {
                m.unlock();
            }
            state.ResumeTiming();
        }
    }
 
    for (std::size_t j = 0; j < i; ++j) {
        mutexes[j].unlock();
    }
}
 
template <typename Mutex>
void GenericUnlock(benchmark::State& state) {
    constexpr std::size_t kMutexCount = 256;
    std::size_t i = 0;
    Mutex mutexes[kMutexCount];
 
    for (auto& m : mutexes) {
        m.lock();
    }
 
    for ([[maybe_unused]] auto _ : state) {
        mutexes[i].unlock();
 
        if (++i == kMutexCount) {
            state.PauseTiming();
            i = 0;
            for (auto& m : mutexes) {
                m.lock();
            }
            state.ResumeTiming();
        }
    }
 
    for (; i < kMutexCount; ++i) {
        mutexes[i].unlock();
    }
}
 
template <typename Mutex>
void GenericContention(benchmark::State& state) {
    std::atomic<std::size_t> lock_unlock_count{0};
    concurrent::impl::InterferenceShield<Mutex> m;
 
    RunParallelBenchmark(state, [&](auto& range) {
        std::uint64_t local_lock_unlock_count = 0;
 
        for ([[maybe_unused]] auto _ : range) {
            m->lock();
            m->unlock();
            ++local_lock_unlock_count;
        }
 
        lock_unlock_count += local_lock_unlock_count;
    });
 
    const auto total_lock_unlock_count = static_cast<double>(lock_unlock_count.load());
    state.counters["locks"] = benchmark::Counter(total_lock_unlock_count, benchmark::Counter::kIsRate);
    state.counters["locks-per-thread"] =
        benchmark::Counter(total_lock_unlock_count / state.range(0), benchmark::Counter::kIsRate);
}
 
template <typename Mutex>
void GenericContentionWithPayload(benchmark::State& state) {
    std::atomic<std::uint64_t> lock_unlock_count{0};
    concurrent::impl::InterferenceShield<Mutex> m;
 
    RunParallelBenchmark(state, [&](auto& range) {
        std::uint64_t local_lock_unlock_count = 0;
 
        for ([[maybe_unused]] auto _ : range) {
            m->lock();
            for (int i = 0; i < 10; ++i) {
                benchmark::DoNotOptimize(utils::Rand());
            }
            m->unlock();
            ++local_lock_unlock_count;
        }
 
        lock_unlock_count += local_lock_unlock_count;
    });
 
    const auto total_lock_unlock_count = static_cast<double>(lock_unlock_count.load());
    state.counters["locks"] = benchmark::Counter(total_lock_unlock_count, benchmark::Counter::kIsRate);
    state.counters["locks-per-thread"] =
        benchmark::Counter(total_lock_unlock_count / state.range(0), benchmark::Counter::kIsRate);
}

 
// Note: We intentionally do not run std::* benchmarks from RunStandalone to
// avoid any side-effects (RunStandalone spawns additional std::threads and uses
// some synchronization primitives).
 
void MutexCoroLock(benchmark::State& state) {
    engine::RunStandalone([&] { GenericLock<engine::Mutex>(state); });
}
 
void MutexStdLock(benchmark::State& state) { GenericLock<std::mutex>(state); }
 
void SingleWaitingTaskMutexLock(benchmark::State& state) {
    engine::RunStandalone([&] { GenericLock<engine::SingleWaitingTaskMutex>(state); });
}
 
void MutexCoroUnlock(benchmark::State& state) {
    engine::RunStandalone([&] { GenericUnlock<engine::Mutex>(state); });
}
 
void MutexStdUnlock(benchmark::State& state) { GenericLock<std::mutex>(state); }
 
void SingleWaitingTaskMutexUnlock(benchmark::State& state) {
    engine::RunStandalone([&] { GenericUnlock<engine::SingleWaitingTaskMutex>(state); });
}
 
void MutexCoroContention(benchmark::State& state) {
    engine::RunStandalone(state.range(0), [&] { GenericContention<engine::Mutex>(state); });
}
 
void MutexStdContention(benchmark::State& state) { GenericContention<std::mutex>(state); }
 
void SingleWaitingTaskMutexContention(benchmark::State& state) {
    engine::RunStandalone(state.range(0), [&] { GenericContention<engine::SingleWaitingTaskMutex>(state); });
}
 
void MutexCoroContentionWithPayload(benchmark::State& state) {
    engine::RunStandalone(state.range(0), [&] { GenericContentionWithPayload<engine::Mutex>(state); });
}
 
void MutexStdContentionWithPayload(benchmark::State& state) { GenericContentionWithPayload<std::mutex>(state); }
 
void SingleWaitingTaskMutexContentionWithPayload(benchmark::State& state) {
    engine::RunStandalone(state.range(0), [&] { GenericContentionWithPayload<engine::SingleWaitingTaskMutex>(state); });
}
 
}  // namespace
 
BENCHMARK(MutexCoroLock);
BENCHMARK(MutexStdLock);
BENCHMARK(SingleWaitingTaskMutexLock);
 
BENCHMARK(MutexCoroUnlock);
BENCHMARK(MutexStdUnlock);
BENCHMARK(SingleWaitingTaskMutexUnlock);
 
BENCHMARK(MutexCoroContention)->RangeMultiplier(2)->Range(1, 32);
BENCHMARK(MutexStdContention)->RangeMultiplier(2)->Range(1, 32);
BENCHMARK(SingleWaitingTaskMutexContention)->Range(1, 2);
 
BENCHMARK(MutexCoroContentionWithPayload)->RangeMultiplier(2)->Range(1, 32);
BENCHMARK(MutexStdContentionWithPayload)->RangeMultiplier(2)->Range(1, 32);
BENCHMARK(SingleWaitingTaskMutexContentionWithPayload)->Range(1, 2);
 
USERVER_NAMESPACE_END