From 20e3ec92b96e0a55b80dcd04917a392502ee3f0c Mon Sep 17 00:00:00 2001 From: Bartosz Taudul Date: Sun, 14 Nov 2021 18:27:25 +0100 Subject: [PATCH] Replace readerwriterqueue with SPSCQueue. --- client/tracy_SPSCQueue.h | 227 ++++++ client/tracy_readerwriterqueue.h | 1128 ------------------------------ 2 files changed, 227 insertions(+), 1128 deletions(-) create mode 100644 client/tracy_SPSCQueue.h delete mode 100644 client/tracy_readerwriterqueue.h diff --git a/client/tracy_SPSCQueue.h b/client/tracy_SPSCQueue.h new file mode 100644 index 00000000..abbfb4c0 --- /dev/null +++ b/client/tracy_SPSCQueue.h @@ -0,0 +1,227 @@ +/* +Copyright (c) 2020 Erik Rigtorp + +Permission is hereby granted, free of charge, to any person obtaining a copy +of this software and associated documentation files (the "Software"), to deal +in the Software without restriction, including without limitation the rights +to use, copy, modify, merge, publish, distribute, sublicense, and/or sell +copies of the Software, and to permit persons to whom the Software is +furnished to do so, subject to the following conditions: + +The above copyright notice and this permission notice shall be included in all +copies or substantial portions of the Software. + +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE +SOFTWARE. + */ + +#pragma once + +#include +#include +#include +#include // std::allocator +#include // std::hardware_destructive_interference_size +#include +#include // std::enable_if, std::is_*_constructible + +namespace rigtorp { + +template > class SPSCQueue { + +#if defined(__cpp_if_constexpr) && defined(__cpp_lib_void_t) + template + struct has_allocate_at_least : std::false_type {}; + + template + struct has_allocate_at_least< + Alloc2, std::void_t().allocate_at_least( + size_t{}))>> : std::true_type {}; +#endif + +public: + explicit SPSCQueue(const size_t capacity, + const Allocator &allocator = Allocator()) + : capacity_(capacity), allocator_(allocator) { + // The queue needs at least one element + if (capacity_ < 1) { + capacity_ = 1; + } + capacity_++; // Needs one slack element + // Prevent overflowing size_t + if (capacity_ > SIZE_MAX - 2 * kPadding) { + capacity_ = SIZE_MAX - 2 * kPadding; + } + +#if defined(__cpp_if_constexpr) && defined(__cpp_lib_void_t) + if constexpr (has_allocate_at_least::value) { + auto res = allocator_.allocate_at_least(capacity_ + 2 * kPadding); + slots_ = res.ptr; + capacity_ = res.count - 2 * kPadding; + } else { + slots_ = std::allocator_traits::allocate( + allocator_, capacity_ + 2 * kPadding); + } +#else + slots_ = std::allocator_traits::allocate( + allocator_, capacity_ + 2 * kPadding); +#endif + + static_assert(alignof(SPSCQueue) == kCacheLineSize, ""); + static_assert(sizeof(SPSCQueue) >= 3 * kCacheLineSize, ""); + assert(reinterpret_cast(&readIdx_) - + reinterpret_cast(&writeIdx_) >= + static_cast(kCacheLineSize)); + } + + ~SPSCQueue() { + while (front()) { + pop(); + } + std::allocator_traits::deallocate(allocator_, slots_, + capacity_ + 2 * kPadding); + } + + // non-copyable and non-movable + SPSCQueue(const SPSCQueue &) = delete; + SPSCQueue &operator=(const SPSCQueue &) = delete; + + template + void emplace(Args &&...args) noexcept( + std::is_nothrow_constructible::value) { + static_assert(std::is_constructible::value, + "T must be constructible with Args&&..."); + auto const writeIdx = writeIdx_.load(std::memory_order_relaxed); + auto nextWriteIdx = writeIdx + 1; + if (nextWriteIdx == capacity_) { + nextWriteIdx = 0; + } + while (nextWriteIdx == readIdxCache_) { + readIdxCache_ = readIdx_.load(std::memory_order_acquire); + } + new (&slots_[writeIdx + kPadding]) T(std::forward(args)...); + writeIdx_.store(nextWriteIdx, std::memory_order_release); + } + + template + bool try_emplace(Args &&...args) noexcept( + std::is_nothrow_constructible::value) { + static_assert(std::is_constructible::value, + "T must be constructible with Args&&..."); + auto const writeIdx = writeIdx_.load(std::memory_order_relaxed); + auto nextWriteIdx = writeIdx + 1; + if (nextWriteIdx == capacity_) { + nextWriteIdx = 0; + } + if (nextWriteIdx == readIdxCache_) { + readIdxCache_ = readIdx_.load(std::memory_order_acquire); + if (nextWriteIdx == readIdxCache_) { + return false; + } + } + new (&slots_[writeIdx + kPadding]) T(std::forward(args)...); + writeIdx_.store(nextWriteIdx, std::memory_order_release); + return true; + } + + void push(const T &v) noexcept(std::is_nothrow_copy_constructible::value) { + static_assert(std::is_copy_constructible::value, + "T must be copy constructible"); + emplace(v); + } + + template ::value>::type> + void push(P &&v) noexcept(std::is_nothrow_constructible::value) { + emplace(std::forward

(v)); + } + + bool + try_push(const T &v) noexcept(std::is_nothrow_copy_constructible::value) { + static_assert(std::is_copy_constructible::value, + "T must be copy constructible"); + return try_emplace(v); + } + + template ::value>::type> + bool try_push(P &&v) noexcept(std::is_nothrow_constructible::value) { + return try_emplace(std::forward

(v)); + } + + T *front() noexcept { + auto const readIdx = readIdx_.load(std::memory_order_relaxed); + if (readIdx == writeIdxCache_) { + writeIdxCache_ = writeIdx_.load(std::memory_order_acquire); + if (writeIdxCache_ == readIdx) { + return nullptr; + } + } + return &slots_[readIdx + kPadding]; + } + + void pop() noexcept { + static_assert(std::is_nothrow_destructible::value, + "T must be nothrow destructible"); + auto const readIdx = readIdx_.load(std::memory_order_relaxed); + assert(writeIdx_.load(std::memory_order_acquire) != readIdx); + slots_[readIdx + kPadding].~T(); + auto nextReadIdx = readIdx + 1; + if (nextReadIdx == capacity_) { + nextReadIdx = 0; + } + readIdx_.store(nextReadIdx, std::memory_order_release); + } + + size_t size() const noexcept { + std::ptrdiff_t diff = writeIdx_.load(std::memory_order_acquire) - + readIdx_.load(std::memory_order_acquire); + if (diff < 0) { + diff += capacity_; + } + return static_cast(diff); + } + + bool empty() const noexcept { return size() == 0; } + + size_t capacity() const noexcept { return capacity_ - 1; } + +private: +#ifdef __cpp_lib_hardware_interference_size + static constexpr size_t kCacheLineSize = + std::hardware_destructive_interference_size; +#else + static constexpr size_t kCacheLineSize = 64; +#endif + + // Padding to avoid false sharing between slots_ and adjacent allocations + static constexpr size_t kPadding = (kCacheLineSize - 1) / sizeof(T) + 1; + +private: + size_t capacity_; + T *slots_; +#if defined(__has_cpp_attribute) && __has_cpp_attribute(no_unique_address) + Allocator allocator_ [[no_unique_address]]; +#else + Allocator allocator_; +#endif + + // Align to cache line size in order to avoid false sharing + // readIdxCache_ and writeIdxCache_ is used to reduce the amount of cache + // coherency traffic + alignas(kCacheLineSize) std::atomic writeIdx_ = {0}; + alignas(kCacheLineSize) size_t readIdxCache_ = 0; + alignas(kCacheLineSize) std::atomic readIdx_ = {0}; + alignas(kCacheLineSize) size_t writeIdxCache_ = 0; + + // Padding to avoid adjacent allocations to share cache line with + // writeIdxCache_ + char padding_[kCacheLineSize - sizeof(writeIdxCache_)]; +}; +} // namespace rigtorp diff --git a/client/tracy_readerwriterqueue.h b/client/tracy_readerwriterqueue.h deleted file mode 100644 index f627d035..00000000 --- a/client/tracy_readerwriterqueue.h +++ /dev/null @@ -1,1128 +0,0 @@ -// Simplified BSD License: -// -// Copyright (c) 2013-2021, Cameron Desrochers -// All rights reserved. -// -// Redistribution and use in source and binary forms, with or without modification, -// are permitted provided that the following conditions are met: -// -// - Redistributions of source code must retain the above copyright notice, this list of -// conditions and the following disclaimer. -// - Redistributions in binary form must reproduce the above copyright notice, this list of -// conditions and the following disclaimer in the documentation and/or other materials -// provided with the distribution. -// -// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY -// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF -// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL -// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, -// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT -// OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) -// HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR -// TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, -// EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. - - -// ©2013-2020 Cameron Desrochers. -// Distributed under the simplified BSD license (see the license file that -// should have come with this header). - -// atomicops.h - -// ©2013-2016 Cameron Desrochers. -// Distributed under the simplified BSD license (see the license file that -// should have come with this header). - -#pragma once - -// Provides portable (VC++2010+, Intel ICC 13, GCC 4.7+, and anything C++11 compliant) implementation -// of low-level memory barriers, plus a few semi-portable utility macros (for inlining and alignment). -// Also has a basic atomic type (limited to hardware-supported atomics with no memory ordering guarantees). -// Uses the AE_* prefix for macros (historical reasons), and the "moodycamel" namespace for symbols. - -#include -#include -#include -#include -#include -#include - -#include "../common/TracyAlloc.hpp" - -// Platform detection -#if defined(__INTEL_COMPILER) -#define AE_ICC -#elif defined(_MSC_VER) -#define AE_VCPP -#elif defined(__GNUC__) -#define AE_GCC -#endif - -#if defined(_M_IA64) || defined(__ia64__) -#define AE_ARCH_IA64 -#elif defined(_WIN64) || defined(__amd64__) || defined(_M_X64) || defined(__x86_64__) -#define AE_ARCH_X64 -#elif defined(_M_IX86) || defined(__i386__) -#define AE_ARCH_X86 -#elif defined(_M_PPC) || defined(__powerpc__) -#define AE_ARCH_PPC -#else -#define AE_ARCH_UNKNOWN -#endif - - -// AE_UNUSED -#define AE_UNUSED(x) ((void)x) - -// AE_NO_TSAN -#if defined(__has_feature) -#if __has_feature(thread_sanitizer) -#define AE_NO_TSAN __attribute__((no_sanitize("thread"))) -#else -#define AE_NO_TSAN -#endif -#else -#define AE_NO_TSAN -#endif - - -// AE_FORCEINLINE -#if defined(AE_VCPP) || defined(AE_ICC) -#define AE_FORCEINLINE __forceinline -#elif defined(AE_GCC) -//#define AE_FORCEINLINE __attribute__((always_inline)) -#define AE_FORCEINLINE inline -#else -#define AE_FORCEINLINE inline -#endif - - -// AE_ALIGN -#if defined(AE_VCPP) || defined(AE_ICC) -#define AE_ALIGN(x) __declspec(align(x)) -#elif defined(AE_GCC) -#define AE_ALIGN(x) __attribute__((aligned(x))) -#else -// Assume GCC compliant syntax... -#define AE_ALIGN(x) __attribute__((aligned(x))) -#endif - - -// Portable atomic fences implemented below: - -namespace tracy { - -enum memory_order { - memory_order_relaxed, - memory_order_acquire, - memory_order_release, - memory_order_acq_rel, - memory_order_seq_cst, - - // memory_order_sync: Forces a full sync: - // #LoadLoad, #LoadStore, #StoreStore, and most significantly, #StoreLoad - memory_order_sync = memory_order_seq_cst -}; - -} // end namespace moodycamel - -#if (defined(AE_VCPP) && (_MSC_VER < 1700 || defined(__cplusplus_cli))) || (defined(AE_ICC) && __INTEL_COMPILER < 1600) - // VS2010 and ICC13 don't support std::atomic_*_fence, implement our own fences - -#include - -#if defined(AE_ARCH_X64) || defined(AE_ARCH_X86) -#define AeFullSync _mm_mfence -#define AeLiteSync _mm_mfence -#elif defined(AE_ARCH_IA64) -#define AeFullSync __mf -#define AeLiteSync __mf -#elif defined(AE_ARCH_PPC) -#include -#define AeFullSync __sync -#define AeLiteSync __lwsync -#endif - - -#ifdef AE_VCPP -#pragma warning(push) -#pragma warning(disable: 4365) // Disable erroneous 'conversion from long to unsigned int, signed/unsigned mismatch' error when using `assert` -#ifdef __cplusplus_cli -#pragma managed(push, off) -#endif -#endif - -namespace tracy { - -AE_FORCEINLINE void compiler_fence(memory_order order) AE_NO_TSAN -{ - switch (order) { - case memory_order_relaxed: break; - case memory_order_acquire: _ReadBarrier(); break; - case memory_order_release: _WriteBarrier(); break; - case memory_order_acq_rel: _ReadWriteBarrier(); break; - case memory_order_seq_cst: _ReadWriteBarrier(); break; - default: assert(false); - } -} - -// x86/x64 have a strong memory model -- all loads and stores have -// acquire and release semantics automatically (so only need compiler -// barriers for those). -#if defined(AE_ARCH_X86) || defined(AE_ARCH_X64) -AE_FORCEINLINE void fence(memory_order order) AE_NO_TSAN -{ - switch (order) { - case memory_order_relaxed: break; - case memory_order_acquire: _ReadBarrier(); break; - case memory_order_release: _WriteBarrier(); break; - case memory_order_acq_rel: _ReadWriteBarrier(); break; - case memory_order_seq_cst: - _ReadWriteBarrier(); - AeFullSync(); - _ReadWriteBarrier(); - break; - default: assert(false); - } -} -#else -AE_FORCEINLINE void fence(memory_order order) AE_NO_TSAN -{ - // Non-specialized arch, use heavier memory barriers everywhere just in case :-( - switch (order) { - case memory_order_relaxed: - break; - case memory_order_acquire: - _ReadBarrier(); - AeLiteSync(); - _ReadBarrier(); - break; - case memory_order_release: - _WriteBarrier(); - AeLiteSync(); - _WriteBarrier(); - break; - case memory_order_acq_rel: - _ReadWriteBarrier(); - AeLiteSync(); - _ReadWriteBarrier(); - break; - case memory_order_seq_cst: - _ReadWriteBarrier(); - AeFullSync(); - _ReadWriteBarrier(); - break; - default: assert(false); - } -} -#endif -} // end namespace moodycamel -#else - // Use standard library of atomics -#include - -namespace tracy { - -AE_FORCEINLINE void compiler_fence(memory_order order) AE_NO_TSAN -{ - switch (order) { - case memory_order_relaxed: break; - case memory_order_acquire: std::atomic_signal_fence(std::memory_order_acquire); break; - case memory_order_release: std::atomic_signal_fence(std::memory_order_release); break; - case memory_order_acq_rel: std::atomic_signal_fence(std::memory_order_acq_rel); break; - case memory_order_seq_cst: std::atomic_signal_fence(std::memory_order_seq_cst); break; - default: assert(false); - } -} - -AE_FORCEINLINE void fence(memory_order order) AE_NO_TSAN -{ - switch (order) { - case memory_order_relaxed: break; - case memory_order_acquire: std::atomic_thread_fence(std::memory_order_acquire); break; - case memory_order_release: std::atomic_thread_fence(std::memory_order_release); break; - case memory_order_acq_rel: std::atomic_thread_fence(std::memory_order_acq_rel); break; - case memory_order_seq_cst: std::atomic_thread_fence(std::memory_order_seq_cst); break; - default: assert(false); - } -} - -} // end namespace moodycamel - -#endif - - -#if !defined(AE_VCPP) || (_MSC_VER >= 1700 && !defined(__cplusplus_cli)) -#define AE_USE_STD_ATOMIC_FOR_WEAK_ATOMIC -#endif - -#ifdef AE_USE_STD_ATOMIC_FOR_WEAK_ATOMIC -#include -#endif -#include - - // WARNING: *NOT* A REPLACEMENT FOR std::atomic. READ CAREFULLY: - // Provides basic support for atomic variables -- no memory ordering guarantees are provided. - // The guarantee of atomicity is only made for types that already have atomic load and store guarantees - // at the hardware level -- on most platforms this generally means aligned pointers and integers (only). -namespace tracy { -template -class weak_atomic -{ -public: - AE_NO_TSAN weak_atomic() : value() { } -#ifdef AE_VCPP -#pragma warning(push) -#pragma warning(disable: 4100) // Get rid of (erroneous) 'unreferenced formal parameter' warning -#endif - template AE_NO_TSAN weak_atomic(U&& x) : value(std::forward(x)) { } -#ifdef __cplusplus_cli - // Work around bug with universal reference/nullptr combination that only appears when /clr is on - AE_NO_TSAN weak_atomic(nullptr_t) : value(nullptr) { } -#endif - AE_NO_TSAN weak_atomic(weak_atomic const& other) : value(other.load()) { } - AE_NO_TSAN weak_atomic(weak_atomic&& other) : value(std::move(other.load())) { } -#ifdef AE_VCPP -#pragma warning(pop) -#endif - - AE_FORCEINLINE operator T() const AE_NO_TSAN { return load(); } - - -#ifndef AE_USE_STD_ATOMIC_FOR_WEAK_ATOMIC - template AE_FORCEINLINE weak_atomic const& operator=(U&& x) AE_NO_TSAN { value = std::forward(x); return *this; } - AE_FORCEINLINE weak_atomic const& operator=(weak_atomic const& other) AE_NO_TSAN { value = other.value; return *this; } - - AE_FORCEINLINE T load() const AE_NO_TSAN { return value; } - - AE_FORCEINLINE T fetch_add_acquire(T increment) AE_NO_TSAN - { -#if defined(AE_ARCH_X64) || defined(AE_ARCH_X86) - if (sizeof(T) == 4) return _InterlockedExchangeAdd((long volatile*)&value, (long)increment); -#if defined(_M_AMD64) - else if (sizeof(T) == 8) return _InterlockedExchangeAdd64((long long volatile*)&value, (long long)increment); -#endif -#else -#error Unsupported platform -#endif - assert(false && "T must be either a 32 or 64 bit type"); - return value; - } - - AE_FORCEINLINE T fetch_add_release(T increment) AE_NO_TSAN - { -#if defined(AE_ARCH_X64) || defined(AE_ARCH_X86) - if (sizeof(T) == 4) return _InterlockedExchangeAdd((long volatile*)&value, (long)increment); -#if defined(_M_AMD64) - else if (sizeof(T) == 8) return _InterlockedExchangeAdd64((long long volatile*)&value, (long long)increment); -#endif -#else -#error Unsupported platform -#endif - assert(false && "T must be either a 32 or 64 bit type"); - return value; - } -#else - template - AE_FORCEINLINE weak_atomic const& operator=(U&& x) AE_NO_TSAN - { - value.store(std::forward(x), std::memory_order_relaxed); - return *this; - } - - AE_FORCEINLINE weak_atomic const& operator=(weak_atomic const& other) AE_NO_TSAN - { - value.store(other.value.load(std::memory_order_relaxed), std::memory_order_relaxed); - return *this; - } - - AE_FORCEINLINE T load() const AE_NO_TSAN { return value.load(std::memory_order_relaxed); } - - AE_FORCEINLINE T fetch_add_acquire(T increment) AE_NO_TSAN - { - return value.fetch_add(increment, std::memory_order_acquire); - } - - AE_FORCEINLINE T fetch_add_release(T increment) AE_NO_TSAN - { - return value.fetch_add(increment, std::memory_order_release); - } -#endif - - -private: -#ifndef AE_USE_STD_ATOMIC_FOR_WEAK_ATOMIC - // No std::atomic support, but still need to circumvent compiler optimizations. - // `volatile` will make memory access slow, but is guaranteed to be reliable. - volatile T value; -#else - std::atomic value; -#endif -}; - -} // end namespace moodycamel - - -#if defined(AE_VCPP) && (_MSC_VER < 1700 || defined(__cplusplus_cli)) -#pragma warning(pop) -#ifdef __cplusplus_cli -#pragma managed(pop) -#endif -#endif - -// end of atomicops.h - -#include -#include -#include -#include -#include -#include -#include -#include // For malloc/free/abort & size_t -#include -#if __cplusplus > 199711L || _MSC_VER >= 1700 // C++11 or VS2012 -#include -#endif - - -// A lock-free queue for a single-consumer, single-producer architecture. -// The queue is also wait-free in the common path (except if more memory -// needs to be allocated, in which case malloc is called). -// Allocates memory sparingly, and only once if the original maximum size -// estimate is never exceeded. -// Tested on x86/x64 processors, but semantics should be correct for all -// architectures (given the right implementations in atomicops.h), provided -// that aligned integer and pointer accesses are naturally atomic. -// Note that there should only be one consumer thread and producer thread; -// Switching roles of the threads, or using multiple consecutive threads for -// one role, is not safe unless properly synchronized. -// Using the queue exclusively from one thread is fine, though a bit silly. - -#ifndef MOODYCAMEL_CACHE_LINE_SIZE -#define MOODYCAMEL_CACHE_LINE_SIZE 64 -#endif - -#ifndef MOODYCAMEL_EXCEPTIONS_ENABLED -#if (defined(_MSC_VER) && defined(_CPPUNWIND)) || (defined(__GNUC__) && defined(__EXCEPTIONS)) || (!defined(_MSC_VER) && !defined(__GNUC__)) -#define MOODYCAMEL_EXCEPTIONS_ENABLED -#endif -#endif - -#ifndef MOODYCAMEL_HAS_EMPLACE -#if !defined(_MSC_VER) || _MSC_VER >= 1800 // variadic templates: either a non-MS compiler or VS >= 2013 -#define MOODYCAMEL_HAS_EMPLACE 1 -#endif -#endif - -#ifndef MOODYCAMEL_MAYBE_ALIGN_TO_CACHELINE -#if defined (__APPLE__) && defined (__MACH__) && __cplusplus >= 201703L -// This is required to find out what deployment target we are using -#include -#if !defined(MAC_OS_X_VERSION_MIN_REQUIRED) || MAC_OS_X_VERSION_MIN_REQUIRED < MAC_OS_X_VERSION_10_14 -// C++17 new(size_t, align_val_t) is not backwards-compatible with older versions of macOS, so we can't support over-alignment in this case -#define MOODYCAMEL_MAYBE_ALIGN_TO_CACHELINE -#endif -#endif -#endif - -#ifndef MOODYCAMEL_MAYBE_ALIGN_TO_CACHELINE -#define MOODYCAMEL_MAYBE_ALIGN_TO_CACHELINE AE_ALIGN(MOODYCAMEL_CACHE_LINE_SIZE) -#endif - -#ifdef AE_VCPP -#pragma warning(push) -#pragma warning(disable: 4324) // structure was padded due to __declspec(align()) -#pragma warning(disable: 4820) // padding was added -#pragma warning(disable: 4127) // conditional expression is constant -#endif - -namespace tracy { - -template -class MOODYCAMEL_MAYBE_ALIGN_TO_CACHELINE ReaderWriterQueue -{ - // Design: Based on a queue-of-queues. The low-level queues are just - // circular buffers with front and tail indices indicating where the - // next element to dequeue is and where the next element can be enqueued, - // respectively. Each low-level queue is called a "block". Each block - // wastes exactly one element's worth of space to keep the design simple - // (if front == tail then the queue is empty, and can't be full). - // The high-level queue is a circular linked list of blocks; again there - // is a front and tail, but this time they are pointers to the blocks. - // The front block is where the next element to be dequeued is, provided - // the block is not empty. The back block is where elements are to be - // enqueued, provided the block is not full. - // The producer thread owns all the tail indices/pointers. The consumer - // thread owns all the front indices/pointers. Both threads read each - // other's variables, but only the owning thread updates them. E.g. After - // the consumer reads the producer's tail, the tail may change before the - // consumer is done dequeuing an object, but the consumer knows the tail - // will never go backwards, only forwards. - // If there is no room to enqueue an object, an additional block (of - // equal size to the last block) is added. Blocks are never removed. - -public: - typedef T value_type; - - // Constructs a queue that can hold at least `size` elements without further - // allocations. If more than MAX_BLOCK_SIZE elements are requested, - // then several blocks of MAX_BLOCK_SIZE each are reserved (including - // at least one extra buffer block). - AE_NO_TSAN explicit ReaderWriterQueue(size_t size = 15) -#ifndef NDEBUG - : enqueuing(false) - ,dequeuing(false) -#endif - { - assert(MAX_BLOCK_SIZE == ceilToPow2(MAX_BLOCK_SIZE) && "MAX_BLOCK_SIZE must be a power of 2"); - assert(MAX_BLOCK_SIZE >= 2 && "MAX_BLOCK_SIZE must be at least 2"); - - Block* firstBlock = nullptr; - - largestBlockSize = ceilToPow2(size + 1); // We need a spare slot to fit size elements in the block - if (largestBlockSize > MAX_BLOCK_SIZE * 2) { - // We need a spare block in case the producer is writing to a different block the consumer is reading from, and - // wants to enqueue the maximum number of elements. We also need a spare element in each block to avoid the ambiguity - // between front == tail meaning "empty" and "full". - // So the effective number of slots that are guaranteed to be usable at any time is the block size - 1 times the - // number of blocks - 1. Solving for size and applying a ceiling to the division gives us (after simplifying): - size_t initialBlockCount = (size + MAX_BLOCK_SIZE * 2 - 3) / (MAX_BLOCK_SIZE - 1); - largestBlockSize = MAX_BLOCK_SIZE; - Block* lastBlock = nullptr; - for (size_t i = 0; i != initialBlockCount; ++i) { - auto block = make_block(largestBlockSize); - if (block == nullptr) { -#ifdef MOODYCAMEL_EXCEPTIONS_ENABLED - throw std::bad_alloc(); -#else - abort(); -#endif - } - if (firstBlock == nullptr) { - firstBlock = block; - } - else { - lastBlock->next = block; - } - lastBlock = block; - block->next = firstBlock; - } - } - else { - firstBlock = make_block(largestBlockSize); - if (firstBlock == nullptr) { -#ifdef MOODYCAMEL_EXCEPTIONS_ENABLED - throw std::bad_alloc(); -#else - abort(); -#endif - } - firstBlock->next = firstBlock; - } - frontBlock = firstBlock; - tailBlock = firstBlock; - - // Make sure the reader/writer threads will have the initialized memory setup above: - fence(memory_order_sync); - } - - // Note: The queue should not be accessed concurrently while it's - // being moved. It's up to the user to synchronize this. - AE_NO_TSAN ReaderWriterQueue(ReaderWriterQueue&& other) - : frontBlock(other.frontBlock.load()), - tailBlock(other.tailBlock.load()), - largestBlockSize(other.largestBlockSize) -#ifndef NDEBUG - ,enqueuing(false) - ,dequeuing(false) -#endif - { - other.largestBlockSize = 32; - Block* b = other.make_block(other.largestBlockSize); - if (b == nullptr) { -#ifdef MOODYCAMEL_EXCEPTIONS_ENABLED - throw std::bad_alloc(); -#else - abort(); -#endif - } - b->next = b; - other.frontBlock = b; - other.tailBlock = b; - } - - // Note: The queue should not be accessed concurrently while it's - // being moved. It's up to the user to synchronize this. - ReaderWriterQueue& operator=(ReaderWriterQueue&& other) AE_NO_TSAN - { - Block* b = frontBlock.load(); - frontBlock = other.frontBlock.load(); - other.frontBlock = b; - b = tailBlock.load(); - tailBlock = other.tailBlock.load(); - other.tailBlock = b; - std::swap(largestBlockSize, other.largestBlockSize); - return *this; - } - - // Note: The queue should not be accessed concurrently while it's - // being deleted. It's up to the user to synchronize this. - AE_NO_TSAN ~ReaderWriterQueue() - { - // Make sure we get the latest version of all variables from other CPUs: - fence(memory_order_sync); - - // Destroy any remaining objects in queue and free memory - Block* frontBlock_ = frontBlock; - Block* block = frontBlock_; - do { - Block* nextBlock = block->next; - size_t blockFront = block->front; - size_t blockTail = block->tail; - - for (size_t i = blockFront; i != blockTail; i = (i + 1) & block->sizeMask) { - auto element = reinterpret_cast(block->data + i * sizeof(T)); - element->~T(); - (void)element; - } - - auto rawBlock = block->rawThis; - block->~Block(); - tracy_free(rawBlock); - block = nextBlock; - } while (block != frontBlock_); - } - - - // Enqueues a copy of element if there is room in the queue. - // Returns true if the element was enqueued, false otherwise. - // Does not allocate memory. - AE_FORCEINLINE bool try_enqueue(T const& element) AE_NO_TSAN - { - return inner_enqueue(element); - } - - // Enqueues a moved copy of element if there is room in the queue. - // Returns true if the element was enqueued, false otherwise. - // Does not allocate memory. - AE_FORCEINLINE bool try_enqueue(T&& element) AE_NO_TSAN - { - return inner_enqueue(std::forward(element)); - } - -#if MOODYCAMEL_HAS_EMPLACE - // Like try_enqueue() but with emplace semantics (i.e. construct-in-place). - template - AE_FORCEINLINE bool try_emplace(Args&&... args) AE_NO_TSAN - { - return inner_enqueue(std::forward(args)...); - } -#endif - - // Enqueues a copy of element on the queue. - // Allocates an additional block of memory if needed. - // Only fails (returns false) if memory allocation fails. - AE_FORCEINLINE bool enqueue(T const& element) AE_NO_TSAN - { - return inner_enqueue(element); - } - - // Enqueues a moved copy of element on the queue. - // Allocates an additional block of memory if needed. - // Only fails (returns false) if memory allocation fails. - AE_FORCEINLINE bool enqueue(T&& element) AE_NO_TSAN - { - return inner_enqueue(std::forward(element)); - } - -#if MOODYCAMEL_HAS_EMPLACE - // Like enqueue() but with emplace semantics (i.e. construct-in-place). - template - AE_FORCEINLINE bool emplace(Args&&... args) AE_NO_TSAN - { - return inner_enqueue(std::forward(args)...); - } -#endif - - // Attempts to dequeue an element; if the queue is empty, - // returns false instead. If the queue has at least one element, - // moves front to result using operator=, then returns true. - template - bool try_dequeue(U& result) AE_NO_TSAN - { -#ifndef NDEBUG - ReentrantGuard guard(this->dequeuing); -#endif - - // High-level pseudocode: - // Remember where the tail block is - // If the front block has an element in it, dequeue it - // Else - // If front block was the tail block when we entered the function, return false - // Else advance to next block and dequeue the item there - - // Note that we have to use the value of the tail block from before we check if the front - // block is full or not, in case the front block is empty and then, before we check if the - // tail block is at the front block or not, the producer fills up the front block *and - // moves on*, which would make us skip a filled block. Seems unlikely, but was consistently - // reproducible in practice. - // In order to avoid overhead in the common case, though, we do a double-checked pattern - // where we have the fast path if the front block is not empty, then read the tail block, - // then re-read the front block and check if it's not empty again, then check if the tail - // block has advanced. - - Block* frontBlock_ = frontBlock.load(); - size_t blockTail = frontBlock_->localTail; - size_t blockFront = frontBlock_->front.load(); - - if (blockFront != blockTail || blockFront != (frontBlock_->localTail = frontBlock_->tail.load())) { - fence(memory_order_acquire); - - non_empty_front_block: - // Front block not empty, dequeue from here - auto element = reinterpret_cast(frontBlock_->data + blockFront * sizeof(T)); - result = std::move(*element); - element->~T(); - - blockFront = (blockFront + 1) & frontBlock_->sizeMask; - - fence(memory_order_release); - frontBlock_->front = blockFront; - } - else if (frontBlock_ != tailBlock.load()) { - fence(memory_order_acquire); - - frontBlock_ = frontBlock.load(); - blockTail = frontBlock_->localTail = frontBlock_->tail.load(); - blockFront = frontBlock_->front.load(); - fence(memory_order_acquire); - - if (blockFront != blockTail) { - // Oh look, the front block isn't empty after all - goto non_empty_front_block; - } - - // Front block is empty but there's another block ahead, advance to it - Block* nextBlock = frontBlock_->next; - // Don't need an acquire fence here since next can only ever be set on the tailBlock, - // and we're not the tailBlock, and we did an acquire earlier after reading tailBlock which - // ensures next is up-to-date on this CPU in case we recently were at tailBlock. - - size_t nextBlockFront = nextBlock->front.load(); - size_t nextBlockTail = nextBlock->localTail = nextBlock->tail.load(); - fence(memory_order_acquire); - - // Since the tailBlock is only ever advanced after being written to, - // we know there's for sure an element to dequeue on it - assert(nextBlockFront != nextBlockTail); - AE_UNUSED(nextBlockTail); - - // We're done with this block, let the producer use it if it needs - fence(memory_order_release); // Expose possibly pending changes to frontBlock->front from last dequeue - frontBlock = frontBlock_ = nextBlock; - - compiler_fence(memory_order_release); // Not strictly needed - - auto element = reinterpret_cast(frontBlock_->data + nextBlockFront * sizeof(T)); - - result = std::move(*element); - element->~T(); - - nextBlockFront = (nextBlockFront + 1) & frontBlock_->sizeMask; - - fence(memory_order_release); - frontBlock_->front = nextBlockFront; - } - else { - // No elements in current block and no other block to advance to - return false; - } - - return true; - } - - - // Returns a pointer to the front element in the queue (the one that - // would be removed next by a call to `try_dequeue` or `pop`). If the - // queue appears empty at the time the method is called, nullptr is - // returned instead. - // Must be called only from the consumer thread. - T* peek() const AE_NO_TSAN - { -#ifndef NDEBUG - ReentrantGuard guard(this->dequeuing); -#endif - // See try_dequeue() for reasoning - - Block* frontBlock_ = frontBlock.load(); - size_t blockTail = frontBlock_->localTail; - size_t blockFront = frontBlock_->front.load(); - - if (blockFront != blockTail || blockFront != (frontBlock_->localTail = frontBlock_->tail.load())) { - fence(memory_order_acquire); - non_empty_front_block: - return reinterpret_cast(frontBlock_->data + blockFront * sizeof(T)); - } - else if (frontBlock_ != tailBlock.load()) { - fence(memory_order_acquire); - frontBlock_ = frontBlock.load(); - blockTail = frontBlock_->localTail = frontBlock_->tail.load(); - blockFront = frontBlock_->front.load(); - fence(memory_order_acquire); - - if (blockFront != blockTail) { - goto non_empty_front_block; - } - - Block* nextBlock = frontBlock_->next; - - size_t nextBlockFront = nextBlock->front.load(); - fence(memory_order_acquire); - - assert(nextBlockFront != nextBlock->tail.load()); - return reinterpret_cast(nextBlock->data + nextBlockFront * sizeof(T)); - } - - return nullptr; - } - - // Removes the front element from the queue, if any, without returning it. - // Returns true on success, or false if the queue appeared empty at the time - // `pop` was called. - bool pop() AE_NO_TSAN - { -#ifndef NDEBUG - ReentrantGuard guard(this->dequeuing); -#endif - // See try_dequeue() for reasoning - - Block* frontBlock_ = frontBlock.load(); - size_t blockTail = frontBlock_->localTail; - size_t blockFront = frontBlock_->front.load(); - - if (blockFront != blockTail || blockFront != (frontBlock_->localTail = frontBlock_->tail.load())) { - fence(memory_order_acquire); - - non_empty_front_block: - auto element = reinterpret_cast(frontBlock_->data + blockFront * sizeof(T)); - element->~T(); - - blockFront = (blockFront + 1) & frontBlock_->sizeMask; - - fence(memory_order_release); - frontBlock_->front = blockFront; - } - else if (frontBlock_ != tailBlock.load()) { - fence(memory_order_acquire); - frontBlock_ = frontBlock.load(); - blockTail = frontBlock_->localTail = frontBlock_->tail.load(); - blockFront = frontBlock_->front.load(); - fence(memory_order_acquire); - - if (blockFront != blockTail) { - goto non_empty_front_block; - } - - // Front block is empty but there's another block ahead, advance to it - Block* nextBlock = frontBlock_->next; - - size_t nextBlockFront = nextBlock->front.load(); - size_t nextBlockTail = nextBlock->localTail = nextBlock->tail.load(); - fence(memory_order_acquire); - - assert(nextBlockFront != nextBlockTail); - AE_UNUSED(nextBlockTail); - - fence(memory_order_release); - frontBlock = frontBlock_ = nextBlock; - - compiler_fence(memory_order_release); - - auto element = reinterpret_cast(frontBlock_->data + nextBlockFront * sizeof(T)); - element->~T(); - - nextBlockFront = (nextBlockFront + 1) & frontBlock_->sizeMask; - - fence(memory_order_release); - frontBlock_->front = nextBlockFront; - } - else { - // No elements in current block and no other block to advance to - return false; - } - - return true; - } - - // Returns the approximate number of items currently in the queue. - // Safe to call from both the producer and consumer threads. - inline size_t size_approx() const AE_NO_TSAN - { - size_t result = 0; - Block* frontBlock_ = frontBlock.load(); - Block* block = frontBlock_; - do { - fence(memory_order_acquire); - size_t blockFront = block->front.load(); - size_t blockTail = block->tail.load(); - result += (blockTail - blockFront) & block->sizeMask; - block = block->next.load(); - } while (block != frontBlock_); - return result; - } - - // Returns the total number of items that could be enqueued without incurring - // an allocation when this queue is empty. - // Safe to call from both the producer and consumer threads. - // - // NOTE: The actual capacity during usage may be different depending on the consumer. - // If the consumer is removing elements concurrently, the producer cannot add to - // the block the consumer is removing from until it's completely empty, except in - // the case where the producer was writing to the same block the consumer was - // reading from the whole time. - inline size_t max_capacity() const { - size_t result = 0; - Block* frontBlock_ = frontBlock.load(); - Block* block = frontBlock_; - do { - fence(memory_order_acquire); - result += block->sizeMask; - block = block->next.load(); - } while (block != frontBlock_); - return result; - } - - -private: - enum AllocationMode { CanAlloc, CannotAlloc }; - -#if MOODYCAMEL_HAS_EMPLACE - template - bool inner_enqueue(Args&&... args) AE_NO_TSAN -#else - template - bool inner_enqueue(U&& element) AE_NO_TSAN -#endif - { -#ifndef NDEBUG - ReentrantGuard guard(this->enqueuing); -#endif - - // High-level pseudocode (assuming we're allowed to alloc a new block): - // If room in tail block, add to tail - // Else check next block - // If next block is not the head block, enqueue on next block - // Else create a new block and enqueue there - // Advance tail to the block we just enqueued to - - Block* tailBlock_ = tailBlock.load(); - size_t blockFront = tailBlock_->localFront; - size_t blockTail = tailBlock_->tail.load(); - - size_t nextBlockTail = (blockTail + 1) & tailBlock_->sizeMask; - if (nextBlockTail != blockFront || nextBlockTail != (tailBlock_->localFront = tailBlock_->front.load())) { - fence(memory_order_acquire); - // This block has room for at least one more element - char* location = tailBlock_->data + blockTail * sizeof(T); -#if MOODYCAMEL_HAS_EMPLACE - new (location) T(std::forward(args)...); -#else - new (location) T(std::forward(element)); -#endif - - fence(memory_order_release); - tailBlock_->tail = nextBlockTail; - } - else { - fence(memory_order_acquire); - if (tailBlock_->next.load() != frontBlock) { - // Note that the reason we can't advance to the frontBlock and start adding new entries there - // is because if we did, then dequeue would stay in that block, eventually reading the new values, - // instead of advancing to the next full block (whose values were enqueued first and so should be - // consumed first). - - fence(memory_order_acquire); // Ensure we get latest writes if we got the latest frontBlock - - // tailBlock is full, but there's a free block ahead, use it - Block* tailBlockNext = tailBlock_->next.load(); - size_t nextBlockFront = tailBlockNext->localFront = tailBlockNext->front.load(); - nextBlockTail = tailBlockNext->tail.load(); - fence(memory_order_acquire); - - // This block must be empty since it's not the head block and we - // go through the blocks in a circle - assert(nextBlockFront == nextBlockTail); - tailBlockNext->localFront = nextBlockFront; - - char* location = tailBlockNext->data + nextBlockTail * sizeof(T); -#if MOODYCAMEL_HAS_EMPLACE - new (location) T(std::forward(args)...); -#else - new (location) T(std::forward(element)); -#endif - - tailBlockNext->tail = (nextBlockTail + 1) & tailBlockNext->sizeMask; - - fence(memory_order_release); - tailBlock = tailBlockNext; - } - else if (canAlloc == CanAlloc) { - // tailBlock is full and there's no free block ahead; create a new block - auto newBlockSize = largestBlockSize >= MAX_BLOCK_SIZE ? largestBlockSize : largestBlockSize * 2; - auto newBlock = make_block(newBlockSize); - if (newBlock == nullptr) { - // Could not allocate a block! - return false; - } - largestBlockSize = newBlockSize; - -#if MOODYCAMEL_HAS_EMPLACE - new (newBlock->data) T(std::forward(args)...); -#else - new (newBlock->data) T(std::forward(element)); -#endif - assert(newBlock->front == 0); - newBlock->tail = newBlock->localTail = 1; - - newBlock->next = tailBlock_->next.load(); - tailBlock_->next = newBlock; - - // Might be possible for the dequeue thread to see the new tailBlock->next - // *without* seeing the new tailBlock value, but this is OK since it can't - // advance to the next block until tailBlock is set anyway (because the only - // case where it could try to read the next is if it's already at the tailBlock, - // and it won't advance past tailBlock in any circumstance). - - fence(memory_order_release); - tailBlock = newBlock; - } - else if (canAlloc == CannotAlloc) { - // Would have had to allocate a new block to enqueue, but not allowed - return false; - } - else { - assert(false && "Should be unreachable code"); - return false; - } - } - - return true; - } - - - // Disable copying - ReaderWriterQueue(ReaderWriterQueue const&) { } - - // Disable assignment - ReaderWriterQueue& operator=(ReaderWriterQueue const&) { } - - - AE_FORCEINLINE static size_t ceilToPow2(size_t x) - { - // From http://graphics.stanford.edu/~seander/bithacks.html#RoundUpPowerOf2 - --x; - x |= x >> 1; - x |= x >> 2; - x |= x >> 4; - for (size_t i = 1; i < sizeof(size_t); i <<= 1) { - x |= x >> (i << 3); - } - ++x; - return x; - } - - template - static AE_FORCEINLINE char* align_for(char* ptr) AE_NO_TSAN - { - const std::size_t alignment = std::alignment_of::value; - return ptr + (alignment - (reinterpret_cast(ptr) % alignment)) % alignment; - } -private: -#ifndef NDEBUG - struct ReentrantGuard - { - AE_NO_TSAN ReentrantGuard(weak_atomic& _inSection) - : inSection(_inSection) - { - assert(!inSection && "Concurrent (or re-entrant) enqueue or dequeue operation detected (only one thread at a time may hold the producer or consumer role)"); - inSection = true; - } - - AE_NO_TSAN ~ReentrantGuard() { inSection = false; } - - private: - ReentrantGuard& operator=(ReentrantGuard const&); - - private: - weak_atomic& inSection; - }; -#endif - - struct Block - { - // Avoid false-sharing by putting highly contended variables on their own cache lines - weak_atomic front; // (Atomic) Elements are read from here - size_t localTail; // An uncontended shadow copy of tail, owned by the consumer - - char cachelineFiller0[MOODYCAMEL_CACHE_LINE_SIZE - sizeof(weak_atomic) - sizeof(size_t)]; - weak_atomic tail; // (Atomic) Elements are enqueued here - size_t localFront; - - char cachelineFiller1[MOODYCAMEL_CACHE_LINE_SIZE - sizeof(weak_atomic) - sizeof(size_t)]; // next isn't very contended, but we don't want it on the same cache line as tail (which is) - weak_atomic next; // (Atomic) - - char* data; // Contents (on heap) are aligned to T's alignment - - const size_t sizeMask; - - - // size must be a power of two (and greater than 0) - AE_NO_TSAN Block(size_t const& _size, char* _rawThis, char* _data) - : front(0UL), localTail(0), tail(0UL), localFront(0), next(nullptr), data(_data), sizeMask(_size - 1), rawThis(_rawThis) - { - } - - private: - // C4512 - Assignment operator could not be generated - Block& operator=(Block const&); - - public: - char* rawThis; - }; - - - static Block* make_block(size_t capacity) AE_NO_TSAN - { - // Allocate enough memory for the block itself, as well as all the elements it will contain - auto size = sizeof(Block) + std::alignment_of::value - 1; - size += sizeof(T) * capacity + std::alignment_of::value - 1; - auto newBlockRaw = static_cast(tracy_malloc(size)); - if (newBlockRaw == nullptr) { - return nullptr; - } - - auto newBlockAligned = align_for(newBlockRaw); - auto newBlockData = align_for(newBlockAligned + sizeof(Block)); - return new (newBlockAligned) Block(capacity, newBlockRaw, newBlockData); - } - -private: - weak_atomic frontBlock; // (Atomic) Elements are dequeued from this block - - char cachelineFiller[MOODYCAMEL_CACHE_LINE_SIZE - sizeof(weak_atomic)]; - weak_atomic tailBlock; // (Atomic) Elements are enqueued to this block - - size_t largestBlockSize; - -#ifndef NDEBUG - weak_atomic enqueuing; - mutable weak_atomic dequeuing; -#endif -}; - -} // end namespace moodycamel - -#ifdef AE_VCPP -#pragma warning(pop) -#endif