bounded_threadsafe_queue: Refactor Pop

Introduces PopModes to bring waiting logic into Pop, similar to Push.
This commit is contained in:
Morph 2023-03-19 15:17:21 -04:00
parent 8c56481249
commit 197d756560

View File

@ -22,52 +22,38 @@ class SPSCQueue {
static_assert((Capacity & (Capacity - 1)) == 0, "Capacity must be a power of two."); static_assert((Capacity & (Capacity - 1)) == 0, "Capacity must be a power of two.");
public: public:
bool TryPush(T&& t) {
return Push<PushMode::Try>(std::move(t));
}
template <typename... Args> template <typename... Args>
bool TryEmplace(Args&&... args) { bool TryEmplace(Args&&... args) {
return Emplace<PushMode::Try>(std::forward<Args>(args)...); return Emplace<PushMode::Try>(std::forward<Args>(args)...);
} }
void PushWait(T&& t) {
Push<PushMode::Wait>(std::move(t));
}
template <typename... Args> template <typename... Args>
void EmplaceWait(Args&&... args) { void EmplaceWait(Args&&... args) {
Emplace<PushMode::Wait>(std::forward<Args>(args)...); Emplace<PushMode::Wait>(std::forward<Args>(args)...);
} }
bool TryPop(T& t) { bool TryPop(T& t) {
return Pop(t); return Pop<PopMode::Try>(t);
}
void PopWait(T& t) {
Pop<PopMode::Wait>(t);
} }
void PopWait(T& t, std::stop_token stop_token) { void PopWait(T& t, std::stop_token stop_token) {
ConsumerWait(stop_token); Pop<PopMode::WaitWithStopToken>(t, stop_token);
Pop(t);
} }
T PopWait(std::stop_token stop_token) { T PopWait() {
ConsumerWait(stop_token);
T t; T t;
Pop(t); Pop<PopMode::Wait>(t);
return t; return t;
} }
void Clear() { T PopWait(std::stop_token stop_token) {
while (!Empty()) { T t;
Pop(); Pop<PopMode::WaitWithStopToken>(t, stop_token);
} return t;
}
bool Empty() const {
return m_read_index.load() == m_write_index.load();
}
size_t Size() const {
return m_write_index.load() - m_read_index.load();
} }
private: private:
@ -77,55 +63,27 @@ private:
Count, Count,
}; };
template <PushMode Mode> enum class PopMode {
bool Push(T&& t) { Try,
const size_t write_index = m_write_index.load(); Wait,
WaitWithStopToken,
if constexpr (Mode == PushMode::Try) { Count,
// Check if we have free slots to write to. };
if ((write_index - m_read_index.load()) == 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()) < Capacity;
});
} else {
static_assert(Mode < PushMode::Count, "Invalid PushMode.");
}
// Determine the position to write to.
const size_t pos = write_index % Capacity;
// Push into the queue.
m_data[pos] = std::move(t);
// 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();
return true;
}
template <PushMode Mode, typename... Args> template <PushMode Mode, typename... Args>
bool Emplace(Args&&... args) { bool Emplace(Args&&... args) {
const size_t write_index = m_write_index.load(); const size_t write_index = m_write_index.load(std::memory_order::relaxed);
if constexpr (Mode == PushMode::Try) { if constexpr (Mode == PushMode::Try) {
// Check if we have free slots to write to. // Check if we have free slots to write to.
if ((write_index - m_read_index.load()) == Capacity) { if ((write_index - m_read_index.load(std::memory_order::acquire)) == Capacity) {
return false; return false;
} }
} else if constexpr (Mode == PushMode::Wait) { } else if constexpr (Mode == PushMode::Wait) {
// Wait until we have free slots to write to. // Wait until we have free slots to write to.
std::unique_lock lock{producer_cv_mutex}; std::unique_lock lock{producer_cv_mutex};
producer_cv.wait(lock, [this, write_index] { producer_cv.wait(lock, [this, write_index] {
return (write_index - m_read_index.load()) < Capacity; return (write_index - m_read_index.load(std::memory_order::acquire)) < Capacity;
}); });
} else { } else {
static_assert(Mode < PushMode::Count, "Invalid PushMode."); static_assert(Mode < PushMode::Count, "Invalid PushMode.");
@ -147,35 +105,33 @@ private:
return true; return true;
} }
void Pop() { template <PopMode Mode>
const size_t read_index = m_read_index.load(); 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. // Check if the queue is empty.
if (read_index == m_write_index.load()) { if (read_index == m_write_index.load(std::memory_order::acquire)) {
return;
}
// Determine the position to read from.
const size_t pos = read_index % Capacity;
// Pop the data off the queue, deleting it.
std::destroy_at(std::addressof(m_data[pos]));
// Increment the read index.
++m_read_index;
// Notify the producer that we have popped off the queue.
std::unique_lock lock{producer_cv_mutex};
producer_cv.notify_one();
}
bool Pop(T& t) {
const size_t read_index = m_read_index.load();
// Check if the queue is empty.
if (read_index == m_write_index.load()) {
return false; 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.");
}
// Determine the position to read from. // Determine the position to read from.
const size_t pos = read_index % Capacity; const size_t pos = read_index % Capacity;
@ -193,11 +149,6 @@ private:
return true; return true;
} }
void ConsumerWait(std::stop_token stop_token) {
std::unique_lock lock{consumer_cv_mutex};
Common::CondvarWait(consumer_cv, lock, stop_token, [this] { return !Empty(); });
}
alignas(128) std::atomic_size_t m_read_index{0}; alignas(128) std::atomic_size_t m_read_index{0};
alignas(128) std::atomic_size_t m_write_index{0}; alignas(128) std::atomic_size_t m_write_index{0};
@ -212,22 +163,12 @@ private:
template <typename T, size_t Capacity = detail::DefaultCapacity> template <typename T, size_t Capacity = detail::DefaultCapacity>
class MPSCQueue { class MPSCQueue {
public: public:
bool TryPush(T&& t) {
std::scoped_lock lock{write_mutex};
return spsc_queue.TryPush(std::move(t));
}
template <typename... Args> template <typename... Args>
bool TryEmplace(Args&&... args) { bool TryEmplace(Args&&... args) {
std::scoped_lock lock{write_mutex}; std::scoped_lock lock{write_mutex};
return spsc_queue.TryEmplace(std::forward<Args>(args)...); return spsc_queue.TryEmplace(std::forward<Args>(args)...);
} }
void PushWait(T&& t) {
std::scoped_lock lock{write_mutex};
spsc_queue.PushWait(std::move(t));
}
template <typename... Args> template <typename... Args>
void EmplaceWait(Args&&... args) { void EmplaceWait(Args&&... args) {
std::scoped_lock lock{write_mutex}; std::scoped_lock lock{write_mutex};
@ -238,26 +179,22 @@ public:
return spsc_queue.TryPop(t); return spsc_queue.TryPop(t);
} }
void PopWait(T& t) {
spsc_queue.PopWait(t);
}
void PopWait(T& t, std::stop_token stop_token) { void PopWait(T& t, std::stop_token stop_token) {
spsc_queue.PopWait(t, stop_token); spsc_queue.PopWait(t, stop_token);
} }
T PopWait() {
return spsc_queue.PopWait();
}
T PopWait(std::stop_token stop_token) { T PopWait(std::stop_token stop_token) {
return spsc_queue.PopWait(stop_token); return spsc_queue.PopWait(stop_token);
} }
void Clear() {
spsc_queue.Clear();
}
bool Empty() {
return spsc_queue.Empty();
}
size_t Size() {
return spsc_queue.Size();
}
private: private:
SPSCQueue<T, Capacity> spsc_queue; SPSCQueue<T, Capacity> spsc_queue;
std::mutex write_mutex; std::mutex write_mutex;
@ -266,22 +203,12 @@ private:
template <typename T, size_t Capacity = detail::DefaultCapacity> template <typename T, size_t Capacity = detail::DefaultCapacity>
class MPMCQueue { class MPMCQueue {
public: public:
bool TryPush(T&& t) {
std::scoped_lock lock{write_mutex};
return spsc_queue.TryPush(std::move(t));
}
template <typename... Args> template <typename... Args>
bool TryEmplace(Args&&... args) { bool TryEmplace(Args&&... args) {
std::scoped_lock lock{write_mutex}; std::scoped_lock lock{write_mutex};
return spsc_queue.TryEmplace(std::forward<Args>(args)...); return spsc_queue.TryEmplace(std::forward<Args>(args)...);
} }
void PushWait(T&& t) {
std::scoped_lock lock{write_mutex};
spsc_queue.PushWait(std::move(t));
}
template <typename... Args> template <typename... Args>
void EmplaceWait(Args&&... args) { void EmplaceWait(Args&&... args) {
std::scoped_lock lock{write_mutex}; std::scoped_lock lock{write_mutex};
@ -293,31 +220,26 @@ public:
return spsc_queue.TryPop(t); return spsc_queue.TryPop(t);
} }
void PopWait(T& t) {
std::scoped_lock lock{read_mutex};
spsc_queue.PopWait(t);
}
void PopWait(T& t, std::stop_token stop_token) { void PopWait(T& t, std::stop_token stop_token) {
std::scoped_lock lock{read_mutex}; std::scoped_lock lock{read_mutex};
spsc_queue.PopWait(t, stop_token); spsc_queue.PopWait(t, stop_token);
} }
T PopWait() {
std::scoped_lock lock{read_mutex};
return spsc_queue.PopWait();
}
T PopWait(std::stop_token stop_token) { T PopWait(std::stop_token stop_token) {
std::scoped_lock lock{read_mutex}; std::scoped_lock lock{read_mutex};
return spsc_queue.PopWait(stop_token); return spsc_queue.PopWait(stop_token);
} }
void Clear() {
std::scoped_lock lock{read_mutex};
spsc_queue.Clear();
}
bool Empty() {
std::scoped_lock lock{read_mutex};
return spsc_queue.Empty();
}
size_t Size() {
std::scoped_lock lock{read_mutex};
return spsc_queue.Size();
}
private: private:
SPSCQueue<T, Capacity> spsc_queue; SPSCQueue<T, Capacity> spsc_queue;
std::mutex write_mutex; std::mutex write_mutex;