[libcxx-commits] [libcxx] [libc++] Remove atomic_wait benchmarks (PR #158289)
Louis Dionne via libcxx-commits
libcxx-commits at lists.llvm.org
Fri Sep 12 06:03:19 PDT 2025
https://github.com/ldionne created https://github.com/llvm/llvm-project/pull/158289
The atomic_wait benchmarks are great, but in fact they are a bit too great. Indeed, they are so thorough that they overload the system they're running on, meaning they can't be run on our CI infrastructure. The NxN benchmarks even crash my system on macOS.
This patch removes the benchmarks since we're trying to move towards more continuous benchmarking, which requires making a tradeoff between exhaustiveness and ability to run the benchmarks on a regular basis.
Instead, it would be better to rework the benchmarks to make them more lightweight, but I think it is reasonable to do that at a later time in order to unblock continuous performance monitoring ASAP.
>From 88840ae088e466eb87c3191b57bd46b0af31d64c Mon Sep 17 00:00:00 2001
From: Louis Dionne <ldionne.2 at gmail.com>
Date: Fri, 12 Sep 2025 08:59:50 -0400
Subject: [PATCH] [libc++] Remove atomic_wait benchmarks
The atomic_wait benchmarks are great, but in fact they are a bit
too great. Indeed, they are so thorough that they overload the system
they're running on, meaning they can't be run on our CI infrastructure.
The NxN benchmarks even crash my system on macOS.
This patch removes the benchmarks since we're trying to move towards
more continuous benchmarking, which requires making a tradeoff between
exhaustiveness and ability to run the benchmarks on a regular basis.
Instead, it would be better to rework the benchmarks to make them
more lightweight, but I think it is reasonable to do that at a later
time in order to unblock continuous performance monitoring ASAP.
---
.../atomic_wait_1_waiter_1_notifier.bench.cpp | 74 --------
.../atomic_wait_N_waiter_N_notifier.bench.cpp | 167 ------------------
libcxx/test/benchmarks/atomic_wait_helper.h | 92 ----------
...mic_wait_multi_waiter_1_notifier.bench.cpp | 167 ------------------
.../atomic_wait_vs_mutex_lock.bench.cpp | 109 ------------
5 files changed, 609 deletions(-)
delete mode 100644 libcxx/test/benchmarks/atomic_wait_1_waiter_1_notifier.bench.cpp
delete mode 100644 libcxx/test/benchmarks/atomic_wait_N_waiter_N_notifier.bench.cpp
delete mode 100644 libcxx/test/benchmarks/atomic_wait_helper.h
delete mode 100644 libcxx/test/benchmarks/atomic_wait_multi_waiter_1_notifier.bench.cpp
delete mode 100644 libcxx/test/benchmarks/atomic_wait_vs_mutex_lock.bench.cpp
diff --git a/libcxx/test/benchmarks/atomic_wait_1_waiter_1_notifier.bench.cpp b/libcxx/test/benchmarks/atomic_wait_1_waiter_1_notifier.bench.cpp
deleted file mode 100644
index c3d7e6511925d..0000000000000
--- a/libcxx/test/benchmarks/atomic_wait_1_waiter_1_notifier.bench.cpp
+++ /dev/null
@@ -1,74 +0,0 @@
-//===----------------------------------------------------------------------===//
-//
-// 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
-//
-//===----------------------------------------------------------------------===//
-
-// UNSUPPORTED: c++03, c++11, c++14, c++17
-
-#include "atomic_wait_helper.h"
-
-#include <atomic>
-#include <array>
-#include <chrono>
-#include <cstdint>
-#include <numeric>
-#include <stop_token>
-#include <thread>
-
-#include "benchmark/benchmark.h"
-#include "make_test_thread.h"
-
-using namespace std::chrono_literals;
-
-template <class NotifyPolicy, class NumPrioTasks>
-void BM_1_atomic_1_waiter_1_notifier(benchmark::State& state) {
- [[maybe_unused]] std::array<HighPrioTask, NumPrioTasks::value> tasks{};
- std::atomic<std::uint64_t> a;
- auto thread_func = [&](std::stop_token st) { NotifyPolicy::notify(a, st); };
-
- 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_1_atomic_1_waiter_1_notifier<KeepNotifying, NumHighPrioTasks<0>>)
- ->RangeMultiplier(2)
- ->Range(1 << 16, 1 << 18);
-BENCHMARK(BM_1_atomic_1_waiter_1_notifier<NotifyEveryNus<50>, NumHighPrioTasks<0>>)
- ->RangeMultiplier(2)
- ->Range(1 << 10, 1 << 12);
-BENCHMARK(BM_1_atomic_1_waiter_1_notifier<NotifyEveryNus<100>, NumHighPrioTasks<0>>)
- ->RangeMultiplier(2)
- ->Range(1 << 10, 1 << 12);
-
-BENCHMARK(BM_1_atomic_1_waiter_1_notifier<KeepNotifying, NumHighPrioTasks<4>>)
- ->RangeMultiplier(2)
- ->Range(1 << 16, 1 << 18);
-BENCHMARK(BM_1_atomic_1_waiter_1_notifier<NotifyEveryNus<50>, NumHighPrioTasks<4>>)
- ->RangeMultiplier(2)
- ->Range(1 << 10, 1 << 12);
-BENCHMARK(BM_1_atomic_1_waiter_1_notifier<NotifyEveryNus<100>, NumHighPrioTasks<4>>)
- ->RangeMultiplier(2)
- ->Range(1 << 10, 1 << 12);
-
-BENCHMARK(BM_1_atomic_1_waiter_1_notifier<KeepNotifying, NumHighPrioTasks<7>>)
- ->RangeMultiplier(2)
- ->Range(1 << 4, 1 << 6);
-BENCHMARK(BM_1_atomic_1_waiter_1_notifier<NotifyEveryNus<50>, NumHighPrioTasks<7>>)
- ->RangeMultiplier(2)
- ->Range(1 << 3, 1 << 5);
-BENCHMARK(BM_1_atomic_1_waiter_1_notifier<NotifyEveryNus<100>, NumHighPrioTasks<7>>)
- ->RangeMultiplier(2)
- ->Range(1 << 3, 1 << 5);
-
-BENCHMARK_MAIN();
diff --git a/libcxx/test/benchmarks/atomic_wait_N_waiter_N_notifier.bench.cpp b/libcxx/test/benchmarks/atomic_wait_N_waiter_N_notifier.bench.cpp
deleted file mode 100644
index d9b9aa212f602..0000000000000
--- a/libcxx/test/benchmarks/atomic_wait_N_waiter_N_notifier.bench.cpp
+++ /dev/null
@@ -1,167 +0,0 @@
-//===----------------------------------------------------------------------===//
-//
-// 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
-//
-//===----------------------------------------------------------------------===//
-
-// UNSUPPORTED: c++03, c++11, c++14, c++17
-
-#include "atomic_wait_helper.h"
-
-#include <atomic>
-#include <cstdint>
-#include <numeric>
-#include <stop_token>
-#include <pthread.h>
-#include <sched.h>
-#include <thread>
-#include <chrono>
-#include <array>
-
-#include "benchmark/benchmark.h"
-#include "make_test_thread.h"
-
-using namespace std::chrono_literals;
-
-template <class NotifyPolicy, class NumberOfAtomics, class NumPrioTasks>
-void BM_N_atomics_N_waiter_N_notifier(benchmark::State& state) {
- [[maybe_unused]] std::array<HighPrioTask, NumPrioTasks::value> tasks{};
- const std::uint64_t total_loop_test_param = state.range(0);
- constexpr std::uint64_t num_atomics = NumberOfAtomics::value;
- std::vector<std::atomic<std::uint64_t>> atomics(num_atomics);
-
- auto notify_func = [&](std::stop_token st, size_t idx) {
- while (!st.stop_requested()) {
- NotifyPolicy::notify(atomics[idx], st);
- }
- };
-
- 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_N_atomics_N_waiter_N_notifier<KeepNotifying, NumberOfAtomics<2>, NumHighPrioTasks<0>>)
- ->RangeMultiplier(2)
- ->Range(1 << 12, 1 << 14);
-BENCHMARK(BM_N_atomics_N_waiter_N_notifier<KeepNotifying, NumberOfAtomics<3>, NumHighPrioTasks<0>>)
- ->RangeMultiplier(2)
- ->Range(1 << 10, 1 << 12);
-BENCHMARK(BM_N_atomics_N_waiter_N_notifier<KeepNotifying, NumberOfAtomics<5>, NumHighPrioTasks<0>>)
- ->RangeMultiplier(2)
- ->Range(1 << 10, 1 << 12);
-BENCHMARK(BM_N_atomics_N_waiter_N_notifier<KeepNotifying, NumberOfAtomics<7>, NumHighPrioTasks<0>>)
- ->RangeMultiplier(2)
- ->Range(1 << 8, 1 << 10);
-
-BENCHMARK(BM_N_atomics_N_waiter_N_notifier<NotifyEveryNus<50>, NumberOfAtomics<2>, NumHighPrioTasks<0>>)
- ->RangeMultiplier(2)
- ->Range(1 << 10, 1 << 12);
-BENCHMARK(BM_N_atomics_N_waiter_N_notifier<NotifyEveryNus<50>, NumberOfAtomics<3>, NumHighPrioTasks<0>>)
- ->RangeMultiplier(2)
- ->Range(1 << 8, 1 << 10);
-BENCHMARK(BM_N_atomics_N_waiter_N_notifier<NotifyEveryNus<50>, NumberOfAtomics<5>, NumHighPrioTasks<0>>)
- ->RangeMultiplier(2)
- ->Range(1 << 8, 1 << 10);
-BENCHMARK(BM_N_atomics_N_waiter_N_notifier<NotifyEveryNus<50>, NumberOfAtomics<7>, NumHighPrioTasks<0>>)
- ->RangeMultiplier(2)
- ->Range(1 << 6, 1 << 8);
-
-BENCHMARK(BM_N_atomics_N_waiter_N_notifier<NotifyEveryNus<100>, NumberOfAtomics<2>, NumHighPrioTasks<0>>)
- ->RangeMultiplier(2)
- ->Range(1 << 8, 1 << 10);
-BENCHMARK(BM_N_atomics_N_waiter_N_notifier<NotifyEveryNus<100>, NumberOfAtomics<3>, NumHighPrioTasks<0>>)
- ->RangeMultiplier(2)
- ->Range(1 << 8, 1 << 10);
-BENCHMARK(BM_N_atomics_N_waiter_N_notifier<NotifyEveryNus<100>, NumberOfAtomics<5>, NumHighPrioTasks<0>>)
- ->RangeMultiplier(2)
- ->Range(1 << 7, 1 << 9);
-BENCHMARK(BM_N_atomics_N_waiter_N_notifier<NotifyEveryNus<100>, NumberOfAtomics<7>, NumHighPrioTasks<0>>)
- ->RangeMultiplier(2)
- ->Range(1 << 6, 1 << 8);
-
-BENCHMARK(BM_N_atomics_N_waiter_N_notifier<KeepNotifying, NumberOfAtomics<2>, NumHighPrioTasks<4>>)
- ->RangeMultiplier(2)
- ->Range(1 << 7, 1 << 9);
-BENCHMARK(BM_N_atomics_N_waiter_N_notifier<KeepNotifying, NumberOfAtomics<3>, NumHighPrioTasks<4>>)
- ->RangeMultiplier(2)
- ->Range(1 << 7, 1 << 9);
-BENCHMARK(BM_N_atomics_N_waiter_N_notifier<KeepNotifying, NumberOfAtomics<5>, NumHighPrioTasks<4>>)
- ->RangeMultiplier(2)
- ->Range(1 << 6, 1 << 8);
-BENCHMARK(BM_N_atomics_N_waiter_N_notifier<KeepNotifying, NumberOfAtomics<7>, NumHighPrioTasks<4>>)
- ->RangeMultiplier(2)
- ->Range(1 << 4, 1 << 6);
-
-BENCHMARK(BM_N_atomics_N_waiter_N_notifier<NotifyEveryNus<50>, NumberOfAtomics<2>, NumHighPrioTasks<4>>)
- ->RangeMultiplier(2)
- ->Range(1 << 7, 1 << 9);
-BENCHMARK(BM_N_atomics_N_waiter_N_notifier<NotifyEveryNus<50>, NumberOfAtomics<3>, NumHighPrioTasks<4>>)
- ->RangeMultiplier(2)
- ->Range(1 << 7, 1 << 9);
-BENCHMARK(BM_N_atomics_N_waiter_N_notifier<NotifyEveryNus<50>, NumberOfAtomics<5>, NumHighPrioTasks<4>>)
- ->RangeMultiplier(2)
- ->Range(1 << 5, 1 << 7);
-BENCHMARK(BM_N_atomics_N_waiter_N_notifier<NotifyEveryNus<50>, NumberOfAtomics<7>, NumHighPrioTasks<4>>)
- ->RangeMultiplier(2)
- ->Range(1 << 3, 1 << 5);
-
-BENCHMARK(BM_N_atomics_N_waiter_N_notifier<NotifyEveryNus<100>, NumberOfAtomics<2>, NumHighPrioTasks<4>>)
- ->RangeMultiplier(2)
- ->Range(1 << 6, 1 << 8);
-BENCHMARK(BM_N_atomics_N_waiter_N_notifier<NotifyEveryNus<100>, NumberOfAtomics<3>, NumHighPrioTasks<4>>)
- ->RangeMultiplier(2)
- ->Range(1 << 6, 1 << 8);
-BENCHMARK(BM_N_atomics_N_waiter_N_notifier<NotifyEveryNus<100>, NumberOfAtomics<5>, NumHighPrioTasks<4>>)
- ->RangeMultiplier(2)
- ->Range(1 << 5, 1 << 7);
-BENCHMARK(BM_N_atomics_N_waiter_N_notifier<NotifyEveryNus<100>, NumberOfAtomics<7>, NumHighPrioTasks<4>>)
- ->RangeMultiplier(2)
- ->Range(1 << 3, 1 << 5);
-
-BENCHMARK_MAIN();
diff --git a/libcxx/test/benchmarks/atomic_wait_helper.h b/libcxx/test/benchmarks/atomic_wait_helper.h
deleted file mode 100644
index cfdacf9e01688..0000000000000
--- a/libcxx/test/benchmarks/atomic_wait_helper.h
+++ /dev/null
@@ -1,92 +0,0 @@
-//===----------------------------------------------------------------------===//
-//
-// 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
-//
-//===----------------------------------------------------------------------===//
-
-#ifndef TEST_BENCHMARK_ATOMIC_WAIT_HELPER_H
-#define TEST_BENCHMARK_ATOMIC_WAIT_HELPER_H
-
-#include <atomic>
-#include <chrono>
-#include <exception>
-#include <stop_token>
-#include <thread>
-
-struct HighPrioTask {
- sched_param param;
- pthread_attr_t attr_t;
- pthread_t thread;
- std::atomic_bool stopped{false};
-
- HighPrioTask(const HighPrioTask&) = delete;
-
- HighPrioTask() {
- pthread_attr_init(&attr_t);
- pthread_attr_setschedpolicy(&attr_t, SCHED_FIFO);
- param.sched_priority = sched_get_priority_max(SCHED_FIFO);
- pthread_attr_setschedparam(&attr_t, ¶m);
- pthread_attr_setinheritsched(&attr_t, PTHREAD_EXPLICIT_SCHED);
-
- auto thread_fun = [](void* arg) -> void* {
- auto* stop = reinterpret_cast<std::atomic_bool*>(arg);
- while (!stop->load(std::memory_order_relaxed)) {
- // spin
- }
- return nullptr;
- };
-
- if (pthread_create(&thread, &attr_t, thread_fun, &stopped) != 0) {
- throw std::runtime_error("failed to create thread");
- }
- }
-
- ~HighPrioTask() {
- stopped = true;
- pthread_attr_destroy(&attr_t);
- pthread_join(thread, nullptr);
- }
-};
-
-template <std::size_t N>
-struct NumHighPrioTasks {
- static constexpr auto value = N;
-};
-
-template <std::size_t N>
-struct NumWaitingThreads {
- static constexpr auto value = N;
-};
-
-template <std::size_t N>
-struct NumberOfAtomics {
- static constexpr auto value = N;
-};
-
-struct KeepNotifying {
- template <class Atomic>
- static void notify(Atomic& a, std::stop_token st) {
- while (!st.stop_requested()) {
- a.fetch_add(1, std::memory_order_relaxed);
- a.notify_all();
- }
- }
-};
-
-template <std::size_t N>
-struct NotifyEveryNus {
- template <class Atomic>
- static void notify(Atomic& a, std::stop_token st) {
- while (!st.stop_requested()) {
- auto start = std::chrono::system_clock::now();
- a.fetch_add(1, std::memory_order_relaxed);
- a.notify_all();
- while (std::chrono::system_clock::now() - start < std::chrono::microseconds{N}) {
- }
- }
- }
-};
-
-#endif // TEST_BENCHMARK_ATOMIC_WAIT_HELPER_H
\ No newline at end of file
diff --git a/libcxx/test/benchmarks/atomic_wait_multi_waiter_1_notifier.bench.cpp b/libcxx/test/benchmarks/atomic_wait_multi_waiter_1_notifier.bench.cpp
deleted file mode 100644
index a14a6a2ad9c98..0000000000000
--- a/libcxx/test/benchmarks/atomic_wait_multi_waiter_1_notifier.bench.cpp
+++ /dev/null
@@ -1,167 +0,0 @@
-//===----------------------------------------------------------------------===//
-//
-// 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
-//
-//===----------------------------------------------------------------------===//
-
-// UNSUPPORTED: c++03, c++11, c++14, c++17
-
-#include "atomic_wait_helper.h"
-
-#include <atomic>
-#include <cstdint>
-#include <numeric>
-#include <stop_token>
-#include <thread>
-#include <chrono>
-#include <array>
-
-#include "benchmark/benchmark.h"
-#include "make_test_thread.h"
-
-using namespace std::chrono_literals;
-
-template <class NotifyPolicy, class NumWaitingThreads, class NumPrioTasks>
-void BM_1_atomic_multi_waiter_1_notifier(benchmark::State& state) {
- [[maybe_unused]] std::array<HighPrioTask, NumPrioTasks::value> tasks{};
-
- std::atomic<std::uint64_t> a;
- auto notify_func = [&](std::stop_token st) { NotifyPolicy::notify(a, st); };
-
- std::uint64_t total_loop_test_param = state.range(0);
- constexpr auto num_waiting_threads = NumWaitingThreads::value;
- 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_1_atomic_multi_waiter_1_notifier<KeepNotifying, NumWaitingThreads<3>, NumHighPrioTasks<0>>)
- ->RangeMultiplier(2)
- ->Range(1 << 14, 1 << 16);
-BENCHMARK(BM_1_atomic_multi_waiter_1_notifier<KeepNotifying, NumWaitingThreads<7>, NumHighPrioTasks<0>>)
- ->RangeMultiplier(2)
- ->Range(1 << 12, 1 << 14);
-BENCHMARK(BM_1_atomic_multi_waiter_1_notifier<KeepNotifying, NumWaitingThreads<15>, NumHighPrioTasks<0>>)
- ->RangeMultiplier(2)
- ->Range(1 << 10, 1 << 12);
-
-BENCHMARK(BM_1_atomic_multi_waiter_1_notifier<NotifyEveryNus<50>, NumWaitingThreads<3>, NumHighPrioTasks<0>>)
- ->RangeMultiplier(2)
- ->Range(1 << 10, 1 << 12);
-BENCHMARK(BM_1_atomic_multi_waiter_1_notifier<NotifyEveryNus<50>, NumWaitingThreads<7>, NumHighPrioTasks<0>>)
- ->RangeMultiplier(2)
- ->Range(1 << 8, 1 << 10);
-BENCHMARK(BM_1_atomic_multi_waiter_1_notifier<NotifyEveryNus<50>, NumWaitingThreads<15>, NumHighPrioTasks<0>>)
- ->RangeMultiplier(2)
- ->Range(1 << 6, 1 << 8);
-
-BENCHMARK(BM_1_atomic_multi_waiter_1_notifier<NotifyEveryNus<100>, NumWaitingThreads<3>, NumHighPrioTasks<0>>)
- ->RangeMultiplier(2)
- ->Range(1 << 8, 1 << 10);
-BENCHMARK(BM_1_atomic_multi_waiter_1_notifier<NotifyEveryNus<100>, NumWaitingThreads<7>, NumHighPrioTasks<0>>)
- ->RangeMultiplier(2)
- ->Range(1 << 6, 1 << 8);
-BENCHMARK(BM_1_atomic_multi_waiter_1_notifier<NotifyEveryNus<100>, NumWaitingThreads<15>, NumHighPrioTasks<0>>)
- ->RangeMultiplier(2)
- ->Range(1 << 4, 1 << 6);
-
-BENCHMARK(BM_1_atomic_multi_waiter_1_notifier<KeepNotifying, NumWaitingThreads<3>, NumHighPrioTasks<4>>)
- ->RangeMultiplier(2)
- ->Range(1 << 8, 1 << 10);
-BENCHMARK(BM_1_atomic_multi_waiter_1_notifier<KeepNotifying, NumWaitingThreads<7>, NumHighPrioTasks<4>>)
- ->RangeMultiplier(2)
- ->Range(1 << 6, 1 << 8);
-BENCHMARK(BM_1_atomic_multi_waiter_1_notifier<KeepNotifying, NumWaitingThreads<15>, NumHighPrioTasks<4>>)
- ->RangeMultiplier(2)
- ->Range(1 << 4, 1 << 6);
-
-BENCHMARK(BM_1_atomic_multi_waiter_1_notifier<NotifyEveryNus<50>, NumWaitingThreads<3>, NumHighPrioTasks<4>>)
- ->RangeMultiplier(2)
- ->Range(1 << 8, 1 << 10);
-BENCHMARK(BM_1_atomic_multi_waiter_1_notifier<NotifyEveryNus<50>, NumWaitingThreads<7>, NumHighPrioTasks<4>>)
- ->RangeMultiplier(2)
- ->Range(1 << 6, 1 << 8);
-BENCHMARK(BM_1_atomic_multi_waiter_1_notifier<NotifyEveryNus<50>, NumWaitingThreads<15>, NumHighPrioTasks<4>>)
- ->RangeMultiplier(2)
- ->Range(1 << 4, 1 << 6);
-
-BENCHMARK(BM_1_atomic_multi_waiter_1_notifier<NotifyEveryNus<100>, NumWaitingThreads<3>, NumHighPrioTasks<4>>)
- ->RangeMultiplier(2)
- ->Range(1 << 8, 1 << 10);
-BENCHMARK(BM_1_atomic_multi_waiter_1_notifier<NotifyEveryNus<100>, NumWaitingThreads<7>, NumHighPrioTasks<4>>)
- ->RangeMultiplier(2)
- ->Range(1 << 6, 1 << 8);
-BENCHMARK(BM_1_atomic_multi_waiter_1_notifier<NotifyEveryNus<100>, NumWaitingThreads<15>, NumHighPrioTasks<4>>)
- ->RangeMultiplier(2)
- ->Range(1 << 4, 1 << 6);
-
-BENCHMARK(BM_1_atomic_multi_waiter_1_notifier<KeepNotifying, NumWaitingThreads<3>, NumHighPrioTasks<7>>)
- ->RangeMultiplier(2)
- ->Range(1 << 4, 1 << 6);
-BENCHMARK(BM_1_atomic_multi_waiter_1_notifier<KeepNotifying, NumWaitingThreads<7>, NumHighPrioTasks<7>>)
- ->RangeMultiplier(2)
- ->Range(1 << 3, 1 << 5);
-BENCHMARK(BM_1_atomic_multi_waiter_1_notifier<KeepNotifying, NumWaitingThreads<15>, NumHighPrioTasks<7>>)
- ->RangeMultiplier(2)
- ->Range(1 << 2, 1 << 4);
-
-BENCHMARK(BM_1_atomic_multi_waiter_1_notifier<NotifyEveryNus<50>, NumWaitingThreads<3>, NumHighPrioTasks<7>>)
- ->RangeMultiplier(2)
- ->Range(1 << 3, 1 << 5);
-BENCHMARK(BM_1_atomic_multi_waiter_1_notifier<NotifyEveryNus<50>, NumWaitingThreads<7>, NumHighPrioTasks<7>>)
- ->RangeMultiplier(2)
- ->Range(1 << 2, 1 << 4);
-BENCHMARK(BM_1_atomic_multi_waiter_1_notifier<NotifyEveryNus<50>, NumWaitingThreads<15>, NumHighPrioTasks<7>>)
- ->RangeMultiplier(2)
- ->Range(1 << 1, 1 << 3);
-
-BENCHMARK(BM_1_atomic_multi_waiter_1_notifier<NotifyEveryNus<100>, NumWaitingThreads<3>, NumHighPrioTasks<7>>)
- ->RangeMultiplier(2)
- ->Range(1 << 3, 1 << 5);
-BENCHMARK(BM_1_atomic_multi_waiter_1_notifier<NotifyEveryNus<100>, NumWaitingThreads<7>, NumHighPrioTasks<7>>)
- ->RangeMultiplier(2)
- ->Range(1 << 2, 1 << 4);
-BENCHMARK(BM_1_atomic_multi_waiter_1_notifier<NotifyEveryNus<100>, NumWaitingThreads<15>, NumHighPrioTasks<7>>)
- ->RangeMultiplier(2)
- ->Range(1 << 1, 1 << 3);
-
-BENCHMARK_MAIN();
diff --git a/libcxx/test/benchmarks/atomic_wait_vs_mutex_lock.bench.cpp b/libcxx/test/benchmarks/atomic_wait_vs_mutex_lock.bench.cpp
deleted file mode 100644
index a554c721df017..0000000000000
--- a/libcxx/test/benchmarks/atomic_wait_vs_mutex_lock.bench.cpp
+++ /dev/null
@@ -1,109 +0,0 @@
-//===----------------------------------------------------------------------===//
-//
-// 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
-//
-//===----------------------------------------------------------------------===//
-
-// UNSUPPORTED: c++03, c++11, c++14, c++17
-
-#include <atomic>
-#include <cstdint>
-#include <mutex>
-#include <stop_token>
-#include <thread>
-
-#include "benchmark/benchmark.h"
-#include "make_test_thread.h"
-
-using namespace std::chrono_literals;
-
-struct AtomicLock {
- std::atomic<bool>& locked_;
-
- AtomicLock(const AtomicLock&) = delete;
- AtomicLock& operator=(const AtomicLock&) = delete;
-
- AtomicLock(std::atomic<bool>& l) : locked_(l) { lock(); }
- ~AtomicLock() { unlock(); }
-
- void lock() {
- while (true) {
- locked_.wait(true, std::memory_order_relaxed);
- bool expected = false;
- if (locked_.compare_exchange_weak(expected, true, std::memory_order_acquire, std::memory_order_relaxed))
- break;
- }
- }
-
- void unlock() {
- locked_.store(false, std::memory_order_release);
- locked_.notify_all();
- }
-};
-
-// using LockState = std::atomic<bool>;
-// using Lock = AtomicLock;
-
-// using LockState = std::mutex;
-// using Lock = std::unique_lock<std::mutex>;
-
-template <class LockState, class Lock>
-void test_multi_thread_lock_unlock(benchmark::State& state) {
- std::uint64_t total_loop_test_param = state.range(0);
- constexpr auto num_threads = 15;
- std::vector<std::jthread> threads;
- threads.reserve(num_threads);
-
- std::atomic<std::uint64_t> start_flag = 0;
- std::atomic<std::uint64_t> done_count = 0;
-
- LockState lock_state{};
-
- auto func = [&start_flag, &done_count, &lock_state, 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();
-
- // main things under test: locking and unlocking in the loop
- for (std::uint64_t i = 0; i < total_loop_test_param; ++i) {
- Lock l{lock_state};
- }
-
- done_count.fetch_add(1);
- }
- };
-
- for (size_t i = 0; i < num_threads; ++i) {
- threads.emplace_back(support::make_test_jthread(func));
- }
-
- for (auto _ : state) {
- done_count = 0;
- start_flag.fetch_add(1);
- start_flag.notify_all();
- while (done_count < num_threads) {
- std::this_thread::yield();
- }
- }
- for (auto& t : threads) {
- t.request_stop();
- }
- start_flag.fetch_add(1);
- start_flag.notify_all();
- for (auto& t : threads) {
- t.join();
- }
-}
-
-void BM_atomic_wait(benchmark::State& state) { test_multi_thread_lock_unlock<std::atomic<bool>, AtomicLock>(state); }
-BENCHMARK(BM_atomic_wait)->RangeMultiplier(2)->Range(1 << 10, 1 << 20);
-
-void BM_mutex(benchmark::State& state) {
- test_multi_thread_lock_unlock<std::mutex, std::unique_lock<std::mutex>>(state);
-}
-BENCHMARK(BM_mutex)->RangeMultiplier(2)->Range(1 << 10, 1 << 20);
-
-BENCHMARK_MAIN();
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