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-rw-r--r--src/common/bounded_threadsafe_queue.h316
1 files changed, 203 insertions, 113 deletions
diff --git a/src/common/bounded_threadsafe_queue.h b/src/common/bounded_threadsafe_queue.h
index 14e887c70..bd87aa09b 100644
--- a/src/common/bounded_threadsafe_queue.h
+++ b/src/common/bounded_threadsafe_queue.h
@@ -1,159 +1,249 @@
-// SPDX-FileCopyrightText: Copyright (c) 2020 Erik Rigtorp <erik@rigtorp.se>
-// SPDX-License-Identifier: MIT
+// SPDX-FileCopyrightText: Copyright 2023 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
#pragma once
#include <atomic>
-#include <bit>
#include <condition_variable>
-#include <memory>
+#include <cstddef>
#include <mutex>
#include <new>
-#include <type_traits>
-#include <utility>
#include "common/polyfill_thread.h"
namespace Common {
-#if defined(__cpp_lib_hardware_interference_size)
-constexpr size_t hardware_interference_size = std::hardware_destructive_interference_size;
-#else
-constexpr size_t hardware_interference_size = 64;
-#endif
+namespace detail {
+constexpr size_t DefaultCapacity = 0x1000;
+} // namespace detail
+
+template <typename T, size_t Capacity = detail::DefaultCapacity>
+class SPSCQueue {
+ static_assert((Capacity & (Capacity - 1)) == 0, "Capacity must be a power of two.");
-template <typename T, size_t capacity = 0x400>
-class MPSCQueue {
public:
- explicit MPSCQueue() : allocator{std::allocator<Slot<T>>()} {
- // Allocate one extra slot to prevent false sharing on the last slot
- slots = allocator.allocate(capacity + 1);
- // Allocators are not required to honor alignment for over-aligned types
- // (see http://eel.is/c++draft/allocator.requirements#10) so we verify
- // alignment here
- if (reinterpret_cast<uintptr_t>(slots) % alignof(Slot<T>) != 0) {
- allocator.deallocate(slots, capacity + 1);
- throw std::bad_alloc();
- }
- for (size_t i = 0; i < capacity; ++i) {
- std::construct_at(&slots[i]);
- }
- static_assert(std::has_single_bit(capacity), "capacity must be an integer power of 2");
- static_assert(alignof(Slot<T>) == hardware_interference_size,
- "Slot must be aligned to cache line boundary to prevent false sharing");
- static_assert(sizeof(Slot<T>) % hardware_interference_size == 0,
- "Slot size must be a multiple of cache line size to prevent "
- "false sharing between adjacent slots");
- static_assert(sizeof(MPSCQueue) % hardware_interference_size == 0,
- "Queue size must be a multiple of cache line size to "
- "prevent false sharing between adjacent queues");
- }
-
- ~MPSCQueue() noexcept {
- for (size_t i = 0; i < capacity; ++i) {
- std::destroy_at(&slots[i]);
- }
- allocator.deallocate(slots, capacity + 1);
+ template <typename... Args>
+ bool TryEmplace(Args&&... args) {
+ return Emplace<PushMode::Try>(std::forward<Args>(args)...);
}
- // The queue must be both non-copyable and non-movable
- MPSCQueue(const MPSCQueue&) = delete;
- MPSCQueue& operator=(const MPSCQueue&) = delete;
+ template <typename... Args>
+ void EmplaceWait(Args&&... args) {
+ Emplace<PushMode::Wait>(std::forward<Args>(args)...);
+ }
- MPSCQueue(MPSCQueue&&) = delete;
- MPSCQueue& operator=(MPSCQueue&&) = delete;
+ bool TryPop(T& t) {
+ return Pop<PopMode::Try>(t);
+ }
- void Push(const T& v) noexcept {
- static_assert(std::is_nothrow_copy_constructible_v<T>,
- "T must be nothrow copy constructible");
- emplace(v);
+ void PopWait(T& t) {
+ Pop<PopMode::Wait>(t);
}
- template <typename P, typename = std::enable_if_t<std::is_nothrow_constructible_v<T, P&&>>>
- void Push(P&& v) noexcept {
- emplace(std::forward<P>(v));
+ void PopWait(T& t, std::stop_token stop_token) {
+ Pop<PopMode::WaitWithStopToken>(t, stop_token);
}
- void Pop(T& v, std::stop_token stop) noexcept {
- auto const tail = tail_.fetch_add(1);
- auto& slot = slots[idx(tail)];
- if (!slot.turn.test()) {
- std::unique_lock lock{cv_mutex};
- Common::CondvarWait(cv, lock, stop, [&slot] { return slot.turn.test(); });
- }
- v = slot.move();
- slot.destroy();
- slot.turn.clear();
- slot.turn.notify_one();
+ T PopWait() {
+ T t;
+ Pop<PopMode::Wait>(t);
+ return t;
+ }
+
+ T PopWait(std::stop_token stop_token) {
+ T t;
+ Pop<PopMode::WaitWithStopToken>(t, stop_token);
+ return t;
}
private:
- template <typename U = T>
- struct Slot {
- ~Slot() noexcept {
- if (turn.test()) {
- destroy();
+ enum class PushMode {
+ Try,
+ Wait,
+ Count,
+ };
+
+ enum class PopMode {
+ Try,
+ Wait,
+ WaitWithStopToken,
+ Count,
+ };
+
+ template <PushMode Mode, typename... Args>
+ bool Emplace(Args&&... args) {
+ const size_t write_index = m_write_index.load(std::memory_order::relaxed);
+
+ if constexpr (Mode == PushMode::Try) {
+ // Check if we have free slots to write to.
+ if ((write_index - m_read_index.load(std::memory_order::acquire)) == Capacity) {
+ return false;
}
+ } else if constexpr (Mode == PushMode::Wait) {
+ // Wait until we have free slots to write to.
+ std::unique_lock lock{producer_cv_mutex};
+ producer_cv.wait(lock, [this, write_index] {
+ return (write_index - m_read_index.load(std::memory_order::acquire)) < Capacity;
+ });
+ } else {
+ static_assert(Mode < PushMode::Count, "Invalid PushMode.");
}
- template <typename... Args>
- void construct(Args&&... args) noexcept {
- static_assert(std::is_nothrow_constructible_v<U, Args&&...>,
- "T must be nothrow constructible with Args&&...");
- std::construct_at(reinterpret_cast<U*>(&storage), std::forward<Args>(args)...);
- }
+ // Determine the position to write to.
+ const size_t pos = write_index % Capacity;
- void destroy() noexcept {
- static_assert(std::is_nothrow_destructible_v<U>, "T must be nothrow destructible");
- std::destroy_at(reinterpret_cast<U*>(&storage));
- }
+ // Emplace into the queue.
+ std::construct_at(std::addressof(m_data[pos]), std::forward<Args>(args)...);
+
+ // Increment the write index.
+ ++m_write_index;
+
+ // Notify the consumer that we have pushed into the queue.
+ std::scoped_lock lock{consumer_cv_mutex};
+ consumer_cv.notify_one();
- U&& move() noexcept {
- return reinterpret_cast<U&&>(storage);
+ return true;
+ }
+
+ template <PopMode Mode>
+ bool Pop(T& t, [[maybe_unused]] std::stop_token stop_token = {}) {
+ const size_t read_index = m_read_index.load(std::memory_order::relaxed);
+
+ if constexpr (Mode == PopMode::Try) {
+ // Check if the queue is empty.
+ if (read_index == m_write_index.load(std::memory_order::acquire)) {
+ return false;
+ }
+ } else if constexpr (Mode == PopMode::Wait) {
+ // Wait until the queue is not empty.
+ std::unique_lock lock{consumer_cv_mutex};
+ consumer_cv.wait(lock, [this, read_index] {
+ return read_index != m_write_index.load(std::memory_order::acquire);
+ });
+ } else if constexpr (Mode == PopMode::WaitWithStopToken) {
+ // Wait until the queue is not empty.
+ std::unique_lock lock{consumer_cv_mutex};
+ Common::CondvarWait(consumer_cv, lock, stop_token, [this, read_index] {
+ return read_index != m_write_index.load(std::memory_order::acquire);
+ });
+ if (stop_token.stop_requested()) {
+ return false;
+ }
+ } else {
+ static_assert(Mode < PopMode::Count, "Invalid PopMode.");
}
- // Align to avoid false sharing between adjacent slots
- alignas(hardware_interference_size) std::atomic_flag turn{};
- struct aligned_store {
- struct type {
- alignas(U) unsigned char data[sizeof(U)];
- };
- };
- typename aligned_store::type storage;
- };
+ // Determine the position to read from.
+ const size_t pos = read_index % Capacity;
+
+ // Pop the data off the queue, moving it.
+ t = std::move(m_data[pos]);
+
+ // Increment the read index.
+ ++m_read_index;
+
+ // Notify the producer that we have popped off the queue.
+ std::scoped_lock lock{producer_cv_mutex};
+ producer_cv.notify_one();
+
+ return true;
+ }
+
+ alignas(128) std::atomic_size_t m_read_index{0};
+ alignas(128) std::atomic_size_t m_write_index{0};
+ std::array<T, Capacity> m_data;
+
+ std::condition_variable_any producer_cv;
+ std::mutex producer_cv_mutex;
+ std::condition_variable_any consumer_cv;
+ std::mutex consumer_cv_mutex;
+};
+
+template <typename T, size_t Capacity = detail::DefaultCapacity>
+class MPSCQueue {
+public:
+ template <typename... Args>
+ bool TryEmplace(Args&&... args) {
+ std::scoped_lock lock{write_mutex};
+ return spsc_queue.TryEmplace(std::forward<Args>(args)...);
+ }
+
+ template <typename... Args>
+ void EmplaceWait(Args&&... args) {
+ std::scoped_lock lock{write_mutex};
+ spsc_queue.EmplaceWait(std::forward<Args>(args)...);
+ }
+
+ bool TryPop(T& t) {
+ return spsc_queue.TryPop(t);
+ }
+
+ void PopWait(T& t) {
+ spsc_queue.PopWait(t);
+ }
+
+ void PopWait(T& t, std::stop_token stop_token) {
+ spsc_queue.PopWait(t, stop_token);
+ }
+
+ T PopWait() {
+ return spsc_queue.PopWait();
+ }
+
+ T PopWait(std::stop_token stop_token) {
+ return spsc_queue.PopWait(stop_token);
+ }
+
+private:
+ SPSCQueue<T, Capacity> spsc_queue;
+ std::mutex write_mutex;
+};
+
+template <typename T, size_t Capacity = detail::DefaultCapacity>
+class MPMCQueue {
+public:
template <typename... Args>
- void emplace(Args&&... args) noexcept {
- static_assert(std::is_nothrow_constructible_v<T, Args&&...>,
- "T must be nothrow constructible with Args&&...");
- auto const head = head_.fetch_add(1);
- auto& slot = slots[idx(head)];
- slot.turn.wait(true);
- slot.construct(std::forward<Args>(args)...);
- slot.turn.test_and_set();
- cv.notify_one();
+ bool TryEmplace(Args&&... args) {
+ std::scoped_lock lock{write_mutex};
+ return spsc_queue.TryEmplace(std::forward<Args>(args)...);
}
- constexpr size_t idx(size_t i) const noexcept {
- return i & mask;
+ template <typename... Args>
+ void EmplaceWait(Args&&... args) {
+ std::scoped_lock lock{write_mutex};
+ spsc_queue.EmplaceWait(std::forward<Args>(args)...);
}
- static constexpr size_t mask = capacity - 1;
+ bool TryPop(T& t) {
+ std::scoped_lock lock{read_mutex};
+ return spsc_queue.TryPop(t);
+ }
- // Align to avoid false sharing between head_ and tail_
- alignas(hardware_interference_size) std::atomic<size_t> head_{0};
- alignas(hardware_interference_size) std::atomic<size_t> tail_{0};
+ void PopWait(T& t) {
+ std::scoped_lock lock{read_mutex};
+ spsc_queue.PopWait(t);
+ }
- std::mutex cv_mutex;
- std::condition_variable_any cv;
+ void PopWait(T& t, std::stop_token stop_token) {
+ std::scoped_lock lock{read_mutex};
+ spsc_queue.PopWait(t, stop_token);
+ }
- Slot<T>* slots;
- [[no_unique_address]] std::allocator<Slot<T>> allocator;
+ T PopWait() {
+ std::scoped_lock lock{read_mutex};
+ return spsc_queue.PopWait();
+ }
- static_assert(std::is_nothrow_copy_assignable_v<T> || std::is_nothrow_move_assignable_v<T>,
- "T must be nothrow copy or move assignable");
+ T PopWait(std::stop_token stop_token) {
+ std::scoped_lock lock{read_mutex};
+ return spsc_queue.PopWait(stop_token);
+ }
- static_assert(std::is_nothrow_destructible_v<T>, "T must be nothrow destructible");
+private:
+ SPSCQueue<T, Capacity> spsc_queue;
+ std::mutex write_mutex;
+ std::mutex read_mutex;
};
} // namespace Common