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//===----------------------------------------------------------------------===//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include <atomic>
#include <numeric>
#include <thread>
#include "benchmark/benchmark.h"
#include "make_test_thread.h"
using namespace std::chrono_literals;
void BM_atomic_wait_one_thread_one_atomic_wait(benchmark::State& state) {
std::atomic<std::uint64_t> a;
auto thread_func = [&](std::stop_token st) {
while (!st.stop_requested()) {
a.fetch_add(1, std::memory_order_relaxed);
a.notify_all();
}
};
std::uint64_t total_loop_test_param = state.range(0);
auto thread = support::make_test_jthread(thread_func);
for (auto _ : state) {
for (std::uint64_t i = 0; i < total_loop_test_param; ++i) {
auto old = a.load(std::memory_order_relaxed);
a.wait(old);
}
}
}
BENCHMARK(BM_atomic_wait_one_thread_one_atomic_wait)->RangeMultiplier(2)->Range(1 << 10, 1 << 24);
void BM_atomic_wait_multi_thread_one_atomic_wait(benchmark::State& state) {
std::atomic<std::uint64_t> a;
auto notify_func = [&](std::stop_token st) {
while (!st.stop_requested()) {
a.fetch_add(1, std::memory_order_relaxed);
a.notify_all();
}
};
std::uint64_t total_loop_test_param = state.range(0);
constexpr auto num_waiting_threads = 15;
std::vector<std::jthread> wait_threads;
wait_threads.reserve(num_waiting_threads);
auto notify_thread = support::make_test_jthread(notify_func);
std::atomic<std::uint64_t> start_flag = 0;
std::atomic<std::uint64_t> done_count = 0;
auto wait_func = [&a, &start_flag, &done_count, total_loop_test_param](std::stop_token st) {
auto old_start = 0;
while (!st.stop_requested()) {
start_flag.wait(old_start);
old_start = start_flag.load();
for (std::uint64_t i = 0; i < total_loop_test_param; ++i) {
auto old = a.load(std::memory_order_relaxed);
a.wait(old);
}
done_count.fetch_add(1);
}
};
for (size_t i = 0; i < num_waiting_threads; ++i) {
wait_threads.emplace_back(support::make_test_jthread(wait_func));
}
for (auto _ : state) {
done_count = 0;
start_flag.fetch_add(1);
start_flag.notify_all();
while (done_count < num_waiting_threads) {
std::this_thread::yield();
}
}
for (auto& t : wait_threads) {
t.request_stop();
}
start_flag.fetch_add(1);
start_flag.notify_all();
for (auto& t : wait_threads) {
t.join();
}
}
BENCHMARK(BM_atomic_wait_multi_thread_one_atomic_wait)->RangeMultiplier(2)->Range(1 << 10, 1 << 20);
void BM_atomic_wait_multi_thread_wait_different_atomics(benchmark::State& state) {
const std::uint64_t total_loop_test_param = state.range(0);
constexpr std::uint64_t num_atomics = 7;
std::vector<std::atomic<std::uint64_t>> atomics(num_atomics);
auto notify_func = [&](std::stop_token st, size_t idx) {
while (!st.stop_requested()) {
atomics[idx].fetch_add(1, std::memory_order_relaxed);
atomics[idx].notify_all();
}
};
std::atomic<std::uint64_t> start_flag = 0;
std::atomic<std::uint64_t> done_count = 0;
auto wait_func = [&, total_loop_test_param](std::stop_token st, size_t idx) {
auto old_start = 0;
while (!st.stop_requested()) {
start_flag.wait(old_start);
old_start = start_flag.load();
for (std::uint64_t i = 0; i < total_loop_test_param; ++i) {
auto old = atomics[idx].load(std::memory_order_relaxed);
atomics[idx].wait(old);
}
done_count.fetch_add(1);
}
};
std::vector<std::jthread> notify_threads;
notify_threads.reserve(num_atomics);
std::vector<std::jthread> wait_threads;
wait_threads.reserve(num_atomics);
for (size_t i = 0; i < num_atomics; ++i) {
notify_threads.emplace_back(support::make_test_jthread(notify_func, i));
}
for (size_t i = 0; i < num_atomics; ++i) {
wait_threads.emplace_back(support::make_test_jthread(wait_func, i));
}
for (auto _ : state) {
done_count = 0;
start_flag.fetch_add(1);
start_flag.notify_all();
while (done_count < num_atomics) {
std::this_thread::yield();
}
}
for (auto& t : wait_threads) {
t.request_stop();
}
start_flag.fetch_add(1);
start_flag.notify_all();
for (auto& t : wait_threads) {
t.join();
}
}
BENCHMARK(BM_atomic_wait_multi_thread_wait_different_atomics)->RangeMultiplier(2)->Range(1 << 10, 1 << 20);
BENCHMARK_MAIN();
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