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// Uses parts of Quill (https://github.com/odygrd/quill)
// Copyright © 2020-2024 Odysseas Georgoudis & contributors
// Copyright © 2024-2025 Dan R.
// Distributed under the MIT License (http://opensource.org/licenses/MIT)
#pragma once
#include "ITraceSink.h"
#if defined(DEATH_TRACE)
#include "../CommonWindows.h"
#include "../Containers/Array.h"
#include "../Containers/Function.h"
#include "../Containers/SmallVector.h"
#include "../Containers/String.h"
#include <chrono>
#include <string>
#if defined(DEATH_TARGET_ANDROID) || defined(__linux__)
# include <sys/syscall.h>
# include <unistd.h>
#elif defined(__NetBSD__)
# include <lwp.h>
# include <unistd.h>
#elif defined(__FreeBSD__)
# include <sys/thr.h>
# include <unistd.h>
#elif defined(__DragonFly__)
# include <sys/lwp.h>
# include <unistd.h>
#elif defined(__OpenBSD__)
# include <pthread_np.h>
# include <unistd.h>
#elif !defined(DEATH_TARGET_WINDOWS)
# include <pthread.h>
# include <unistd.h>
#endif
#if defined(DEATH_TRACE_ASYNC)
# include "../Base/Format.h"
# include "../Containers/StaticArray.h"
# include "../Containers/StringStl.h"
# include "../Threading/Event.h"
# include "../Threading/Spinlock.h"
# include <atomic>
# include <memory>
# include <mutex>
# include <thread>
# include <limits>
// BoundedSPSCQueue includes
# if defined(DEATH_TARGET_WINDOWS) || defined(DEATH_TARGET_SWITCH) || defined(DEATH_TARGET_VITA)
# include <malloc.h>
# else
# include <sys/mman.h>
# endif
# if defined(DEATH_TARGET_X86)
# if defined(DEATH_TARGET_MSVC)
# include <intrin.h>
# else
# if __has_include(<x86gprintrin.h>)
# if defined(__GNUC__) && __GNUC__ > 10
# include <emmintrin.h>
# include <x86gprintrin.h>
# elif defined(__clang_major__)
// clang needs immintrin for _mm_clflushopt
# include <immintrin.h>
# endif
# else
# include <immintrin.h>
# include <x86intrin.h>
# endif
# endif
# endif
#endif
namespace Death { namespace Trace {
//###==##====#=====--==~--~=~- --- -- - - - -
namespace Implementation
{
DEATH_ALWAYS_INLINE std::uint32_t GetNativeThreadId() noexcept
{
# if defined(DEATH_TARGET_CYGWIN)
return 0; // Not supported
# elif defined(DEATH_TARGET_WINDOWS)
return static_cast<std::uint32_t>(::GetCurrentThreadId());
# elif defined(DEATH_TARGET_ANDROID)
return static_cast<std::uint32_t>(::syscall(__NR_gettid));
# elif defined(__linux__)
return static_cast<std::uint32_t>(::syscall(SYS_gettid));
# elif defined(DEATH_TARGET_APPLE)
std::uint64_t tid64;
pthread_threadid_np(nullptr, &tid64);
return static_cast<std::uint32_t>(tid64);
# elif defined(__NetBSD__)
return static_cast<std::uint32_t>(_lwp_self());
# elif defined(__FreeBSD__)
long lwpid;
thr_self(&lwpid);
return static_cast<std::uint32_t>(lwpid);
# elif defined(__DragonFly__)
return static_cast<std::uint32_t>(lwp_gettid());
# elif defined(__OpenBSD__)
return static_cast<std::uint32_t>(getthrid());
# else
return reinterpret_cast<std::uintptr_t>(pthread_self());
# endif
}
}
#if defined(DEATH_TRACE_ASYNC)
namespace Implementation
{
/** @brief Available queue types to be used inside logger */
enum class QueueType
{
UnboundedBlocking,
UnboundedDropping,
BoundedBlocking,
BoundedDropping
};
/** @brief Default type of underlying queue inside logger */
static constexpr QueueType DefaultQueueType = QueueType::UnboundedBlocking;
/** @brief Initial capacity of queue inside logger */
static constexpr std::uint32_t InitialQueueCapacity = 128 * 1024;
/** @brief Interval between retries for blocking queue types (in nanoseconds) */
static constexpr std::uint32_t BlockingQueueRetryIntervalNanoseconds = 800;
/** @brief Enables huge pages to be used for storage of underlying queue to reduce TBL misses, available only on Linux */
static constexpr bool HugePagesEnabled = false;
/** @brief Initial item capacity of transit event buffer per thread context, must be power of 2 */
static constexpr std::uint32_t TransitEventBufferInitialCapacity = 256;
/** @brief If enabled, the worker thread will process all remaining entries before exiting */
static constexpr bool WaitForQueuesToEmptyBeforeExit = true;
/** @brief Controls the frequency at which the backend recalculates and syncs the internal RdtscClock with the system time from the system wall clock */
static constexpr std::chrono::milliseconds RdtscResyncInterval = std::chrono::milliseconds{500};
/** @brief When the soft limit is reached, the worker thread will try to process a batch of cached transit events all at once */
static constexpr std::size_t TransitEventsSoftLimit = 4096;
/** @brief When hard limit is reached, the worker thread will stop reading the queues until there is space available in the buffer */
static constexpr std::size_t TransitEventsHardLimit = 32768;
/**
@brief When this option is set to a non-zero value, the backend takes a timestamp (`now()`) before reading the queues.
It uses that timestamp to ensure that each log message's timestamp from the frontend queues is less than
or equal to the stored `now()` timestamp minus the specified grace period, guaranteeing ordering by timestamp.
Messages that fail the above check remain in the lock-free queue and they are checked again in the next iteration.
The timestamp check is performed with microsecond precision.
*/
static constexpr std::chrono::microseconds LogTimestampOrderingGracePeriod{250};
/** @brief Special value for level to force immediate flushing of all buffers */
static constexpr TraceLevel FlushRequested = TraceLevel(UINT8_MAX);
/** @brief Special value for level to initialize backtrace storage */
static constexpr TraceLevel InitializeBacktraceRequested = TraceLevel(UINT8_MAX - 1);
/** @brief Special value for level to force immediate flushing of backtrace storage */
static constexpr TraceLevel FlushBacktraceRequested = TraceLevel(UINT8_MAX - 2);
static constexpr std::size_t CacheLineSize = 64u;
static constexpr std::size_t CacheLineAligned = 2 * CacheLineSize;
constexpr bool IsPowerOfTwo(std::uint64_t number) noexcept {
return (number != 0) && ((number & (number - 1)) == 0);
}
template<typename T>
constexpr T MaxPowerOfTwo() noexcept {
return (std::numeric_limits<T>::max() >> 1) + 1;
}
template<typename T>
T NextPowerOfTwo(T n) noexcept {
constexpr T maxPowerOf2 = MaxPowerOfTwo<T>();
if (n >= maxPowerOf2) {
return maxPowerOf2;
}
if (IsPowerOfTwo(static_cast<std::uint64_t>(n))) {
return n;
}
T result = 1;
while (result < n) {
result <<= 1;
}
DEATH_DEBUG_ASSERT(IsPowerOfTwo(static_cast<std::uint64_t>(result)));
return result;
}
/** @brief Returns value of timestamp counter on current thread (if supported) */
# if defined(__aarch64__)
DEATH_ALWAYS_INLINE std::uint64_t rdtsc() noexcept {
// System timer of ARMv8 runs at a different frequency than the CPU's.
// The frequency is fixed, typically in the range 1-50MHz. It can be
// read at CNTFRQ special register. We assume the OS has set up the virtual timer properly.
std::int64_t virtualTimerValue;
__asm__ volatile("mrs %0, cntvct_el0" : "=r"(virtualTimerValue));
return static_cast<uint64_t>(virtualTimerValue);
}
# elif (defined(__ARM_ARCH) && !defined(DEATH_TARGET_MSVC))
DEATH_ALWAYS_INLINE std::uint64_t rdtsc() noexcept {
# if (__ARM_ARCH >= 6)
// V6 is the earliest arch that has a standard cyclecount
std::uint32_t pmccntr;
std::uint32_t pmuseren;
std::uint32_t pmcntenset;
__asm__ volatile("mrc p15, 0, %0, c9, c14, 0" : "=r"(pmuseren));
if (pmuseren & 1) {
__asm__ volatile("mrc p15, 0, %0, c9, c12, 1" : "=r"(pmcntenset));
if (pmcntenset & 0x80000000ul) {
__asm__ volatile("mrc p15, 0, %0, c9, c13, 0" : "=r"(pmccntr));
return (static_cast<uint64_t>(pmccntr)) * 64u;
}
}
# endif
return static_cast<std::uint64_t>(std::chrono::system_clock::now().time_since_epoch().count());
}
# elif defined(__riscv)
DEATH_ALWAYS_INLINE std::uint64_t rdtsc() noexcept {
std::uint64_t tsc;
__asm__ volatile("rdtime %0" : "=r"(tsc));
return tsc;
}
# elif defined(__loongarch64)
DEATH_ALWAYS_INLINE std::uint64_t rdtsc() noexcept {
std::uint64_t tsc;
__asm__ volatile("rdtime.d %0,$r0" : "=r" (tsc));
return tsc;
}
# elif defined(__s390x__)
DEATH_ALWAYS_INLINE std::uint64_t rdtsc() noexcept {
std::uint64_t tsc;
__asm__ volatile("stck %0" : "=Q" (tsc) : : "cc");
return tsc;
}
# elif (defined(_M_ARM) || defined(_M_ARM64) || defined(__PPC64__))
DEATH_ALWAYS_INLINE std::uint64_t rdtsc() noexcept {
return static_cast<std::uint64_t>(std::chrono::system_clock::now().time_since_epoch().count());
}
# else
DEATH_ALWAYS_INLINE std::uint64_t rdtsc() noexcept {
return __rdtsc();
}
# endif
/** @brief Allows to convert timestamp counter values to Unix nanoseconds */
class RdtscClock
{
private:
class RdtscTicks
{
public:
static RdtscTicks& instance();
double nanosecondsPerTick() const noexcept {
return _nanosecondsPerTick;
}
private:
RdtscTicks();
double _nanosecondsPerTick;
};
public:
explicit RdtscClock(std::chrono::nanoseconds resyncInterval);
std::uint64_t timeSinceEpoch(std::uint64_t rdtscValue) const noexcept;
std::uint64_t timeSinceEpochSafe(std::uint64_t rdtscValue) const noexcept;
bool resync(std::uint32_t lag) const noexcept;
double nanosecondsPerTick() const noexcept {
return _nanosecondsPerTick;
}
private:
struct BaseTimeTsc
{
BaseTimeTsc()
: BaseTime(0), BaseTsc(0) {}
/** @brief Initial base time in nanoseconds since epoch */
std::int64_t BaseTime;
/** @brief Initial base tsc time */
std::uint64_t BaseTsc;
};
mutable std::int64_t _resyncIntervalTicks;
std::int64_t _resyncIntervalOriginal;
double _nanosecondsPerTick;
alignas(CacheLineAligned) mutable std::atomic<std::uint32_t> _version;
mutable Containers::StaticArray<2, BaseTimeTsc> _base;
static inline std::uint64_t fastAverage(std::uint64_t x, std::uint64_t y) noexcept {
return (x & y) + ((x ^ y) >> 1);
}
};
/**
* @brief Bounded single-producer single-consumer FIFO queue (ring buffer)
*/
template<typename T>
class BoundedSPSCQueueImpl
{
public:
explicit BoundedSPSCQueueImpl(T capacity, bool hugesPagesEnabled = false, T readerStorePercent = 5)
: _capacity(NextPowerOfTwo(capacity)), _capacityMask(_capacity - 1),
_bytesPerBatch(static_cast<T>(_capacity * static_cast<double>(readerStorePercent) / 100.0)),
_storage(static_cast<std::uint8_t*>(allocAligned(2ULL * static_cast<std::uint64_t>(_capacity), CacheLineAligned, hugesPagesEnabled))),
_hugePagesEnabled(hugesPagesEnabled)
{
std::memset(_storage, 0, 2ULL * static_cast<std::uint64_t>(_capacity));
_atomicWriterPos.store(0);
_atomicReaderPos.store(0);
# if defined(DEATH_TARGET_X86) && defined(DEATH_TARGET_CLFLUSHOPT) && !defined(DEATH_TARGET_CLANG_CL)
// Remove log memory from cache
for (std::uint64_t i = 0; i < (2ULL * static_cast<std::uint64_t>(_capacity)); i += CacheLineSize) {
_mm_clflush(_storage + i);
}
DEATH_DEBUG_ASSERT(_capacity >= 1024);
std::uint64_t cacheLines = (_capacity >= 2048 ? 32 : 16);
for (std::uint64_t i = 0; i < cacheLines; ++i) {
_mm_prefetch(reinterpret_cast<char const*>(_storage + (CacheLineSize * i)), _MM_HINT_T0);
}
# endif
}
~BoundedSPSCQueueImpl() noexcept {
freeAligned(_storage);
}
BoundedSPSCQueueImpl(BoundedSPSCQueueImpl const&) = delete;
BoundedSPSCQueueImpl& operator=(BoundedSPSCQueueImpl const&) = delete;
std::uint8_t* prepareWrite(T n) noexcept {
if ((_capacity - static_cast<T>(_writerPos - _cachedReaderPos)) < n) {
// Not enough space, we need to load reader and re-check
_cachedReaderPos = _atomicReaderPos.load(std::memory_order_acquire);
if ((_capacity - static_cast<T>(_writerPos - _cachedReaderPos)) < n) {
return nullptr;
}
}
return &_storage[_writerPos & _capacityMask];
}
void finishWrite(T nbytes) noexcept {
_writerPos += nbytes;
}
void commitWrite() noexcept {
// Set the atomic flag, so the reader can see write
_atomicWriterPos.store(_writerPos, std::memory_order_release);
# if defined(DEATH_TARGET_X86) && defined(DEATH_TARGET_CLFLUSHOPT) && !defined(DEATH_TARGET_CLANG_CL)
// Flush writen cache lines
flushCacheLines(_lastFlushedWriterPos, _writerPos);
// Prefetch a future cache line
_mm_prefetch(reinterpret_cast<char const*>(_storage + (_writerPos & _capacityMask) + (CacheLineSize * 10)), _MM_HINT_T0);
# endif
}
void finishAndCommitWrite(T nbytes) noexcept {
finishWrite(nbytes);
commitWrite();
}
const std::uint8_t* prepareRead() noexcept {
if (empty()) {
return nullptr;
}
return &_storage[_readerPos & _capacityMask];
}
void finishRead(T nbytes) noexcept {
_readerPos += nbytes;
}
void commitRead() noexcept {
if (static_cast<T>(_readerPos - _atomicReaderPos.load(std::memory_order_relaxed)) >= _bytesPerBatch) {
_atomicReaderPos.store(_readerPos, std::memory_order_release);
# if defined(DEATH_TARGET_X86) && defined(DEATH_TARGET_CLFLUSHOPT) && !defined(DEATH_TARGET_CLANG_CL)
flushCacheLines(_lastFlushedReaderPos, _readerPos);
# endif
}
}
/** @brief Checks if the queue is empty, should be called only by the reader */
bool empty() const noexcept {
if (_writerPosCache == _readerPos) {
// if we think the queue is empty we also load the atomic variable to check further
_writerPosCache = _atomicWriterPos.load(std::memory_order_acquire);
if (_writerPosCache == _readerPos) {
return true;
}
}
return false;
}
T capacity() const noexcept {
return static_cast<T>(_capacity);
}
bool hugePagesEnabled() const noexcept {
return _hugePagesEnabled;
}
private:
static constexpr T CacheLineMask{CacheLineSize - 1};
const T _capacity;
const T _capacityMask;
const T _bytesPerBatch;
std::uint8_t* _storage{nullptr};
const bool _hugePagesEnabled;
alignas(CacheLineAligned) std::atomic<T> _atomicWriterPos{0};
alignas(CacheLineAligned) T _writerPos{0};
T _cachedReaderPos{0};
T _lastFlushedWriterPos{0};
alignas(CacheLineAligned) std::atomic<T> _atomicReaderPos{0};
alignas(CacheLineAligned) T _readerPos{0};
mutable T _writerPosCache{0};
T _lastFlushedReaderPos{0};
# if defined(DEATH_TARGET_X86) && defined(DEATH_TARGET_CLFLUSHOPT) && !defined(DEATH_TARGET_CLANG_CL)
// _mm_clflushopt is supported only since Skylake and requires "-mclflushopt" option on GCC/clang, and is undefined on Clang-CL
void flushCacheLines(T& last, T offset) noexcept {
T lastDiff = last - (last & CacheLineMask);
T curDiff = offset - (offset & CacheLineMask);
if (curDiff > lastDiff) {
std::uint8_t* ptr = _storage + (lastDiff & _capacityMask);
do {
_mm_clflushopt(ptr);
ptr += CacheLineSize;
lastDiff += CacheLineSize;
} while (curDiff > lastDiff);
last = lastDiff;
}
}
# endif
static std::uint8_t* alignPointer(void* pointer, std::size_t alignment) noexcept {
DEATH_DEBUG_ASSERT(IsPowerOfTwo(alignment), "alignment must be a power of two", reinterpret_cast<std::uint8_t*>(pointer));
return reinterpret_cast<std::uint8_t*>((reinterpret_cast<std::uintptr_t>(pointer) + (alignment - 1ul)) &
~(alignment - 1ul));
}
static void* allocAligned(std::size_t size, std::size_t alignment, DEATH_UNUSED bool hugesPagesEnabled) noexcept {
# if defined(DEATH_TARGET_WINDOWS)
void* p = _aligned_malloc(size, alignment);
DEATH_DEBUG_ASSERT(p != nullptr);
return p;
# elif defined(DEATH_TARGET_SWITCH) || defined(DEATH_TARGET_VITA)
void* p = ::memalign(alignment, size);
DEATH_DEBUG_ASSERT(p != nullptr);
return p;
# else
// Calculate the total size including the metadata and alignment
constexpr std::size_t MetadataSize = 2u * sizeof(std::size_t);
std::size_t totalSize = size + MetadataSize + alignment;
// Allocate the memory
int flags = MAP_PRIVATE | MAP_ANONYMOUS;
# if defined(__linux__)
if (hugesPagesEnabled) {
flags |= MAP_HUGETLB;
}
# endif
void* mem = ::mmap(nullptr, totalSize, PROT_READ | PROT_WRITE, flags, -1, 0);
# if defined(__linux__)
if (mem == MAP_FAILED && hugesPagesEnabled) {
flags &= ~MAP_HUGETLB;
mem = ::mmap(nullptr, totalSize, PROT_READ | PROT_WRITE, flags, -1, 0);
}
# endif
DEATH_DEBUG_ASSERT(mem != MAP_FAILED, ("mmap() failed with error {} ({})", errno, strerror(errno)), nullptr);
// Calculate the aligned address after the metadata
std::uint8_t* alignedAddress = alignPointer(static_cast<std::uint8_t*>(mem) + MetadataSize, alignment);
// Calculate the offset from the original memory location
std::size_t offset = static_cast<std::size_t>(alignedAddress - static_cast<std::uint8_t*>(mem));
// Store the size and offset information in the metadata
std::memcpy(alignedAddress - sizeof(std::size_t), &totalSize, sizeof(totalSize));
std::memcpy(alignedAddress - (2u * sizeof(std::size_t)), &offset, sizeof(offset));
return alignedAddress;
# endif
}
static void freeAligned(void* ptr) noexcept {
# if defined(DEATH_TARGET_WINDOWS)
_aligned_free(ptr);
# elif defined(DEATH_TARGET_SWITCH) || defined(DEATH_TARGET_VITA)
::free(ptr);
# else
// Retrieve the size and offset information from the metadata
std::size_t offset;
std::memcpy(&offset, static_cast<std::uint8_t*>(ptr) - (2u * sizeof(std::size_t)), sizeof(offset));
std::size_t totalSize;
std::memcpy(&totalSize, static_cast<std::uint8_t*>(ptr) - sizeof(std::size_t), sizeof(totalSize));
// Calculate the original memory block address
void* mem = static_cast<std::uint8_t*>(ptr) - offset;
::munmap(mem, totalSize);
# endif
}
};
using BoundedSPSCQueue = BoundedSPSCQueueImpl<std::size_t>;
/**
@brief Unbounded single-producer single-consumer FIFO queue (ring buffer)
When the internal circular buffer becomes full, a new one will be created and the production will continue
in the new buffer. Consumption is wait free. If no data is available, a special value is returned.
If a new buffer is created from the producer, the consumer first consumes everything in the old buffer
and then moves to the new buffer.
*/
class UnboundedSPSCQueue
{
private:
struct Node
{
explicit Node(std::size_t boundedQueueCapacity, bool hugePagesEnabled)
: boundedQueue(boundedQueueCapacity, hugePagesEnabled) {}
std::atomic<Node*> next{nullptr};
BoundedSPSCQueue boundedQueue;
};
public:
struct ReadResult
{
explicit ReadResult(const std::uint8_t* readPosition) : readPos(readPosition) {}
const std::uint8_t* readPos;
std::size_t previousCapacity{0};
std::size_t newCapacity{0};
bool allocation{false};
};
explicit UnboundedSPSCQueue(std::size_t initialBoundedQueueCapacity, bool hugesPagesEnabled = false)
: _producer(new Node(initialBoundedQueueCapacity, hugesPagesEnabled)), _consumer(_producer) {}
~UnboundedSPSCQueue() noexcept {
// Get the current consumer node
Node* currentNode = _consumer;
// Look for extra nodes to delete
while (currentNode != nullptr) {
Node* toDelete = currentNode;
currentNode = currentNode->next;
delete toDelete;
}
}
UnboundedSPSCQueue(UnboundedSPSCQueue const&) = delete;
UnboundedSPSCQueue& operator=(UnboundedSPSCQueue const&) = delete;
std::uint8_t* prepareWrite(std::size_t nbytes) noexcept {
// Try to reserve the bounded queue
std::uint8_t* writePos = _producer->boundedQueue.prepareWrite(nbytes);
if DEATH_LIKELY(writePos != nullptr) {
return writePos;
}
return handleFullQueue(nbytes);
}
void finishWrite(std::size_t nbytes) noexcept {
_producer->boundedQueue.finishWrite(nbytes);
}
void commitWrite() noexcept {
_producer->boundedQueue.commitWrite();
}
void finishAndCommitWrite(std::size_t nbytes) noexcept {
finishWrite(nbytes);
commitWrite();
}
std::size_t producerCapacity() const noexcept {
return _producer->boundedQueue.capacity();
}
void shrink(std::size_t capacity) noexcept {
if (capacity > (_producer->boundedQueue.capacity() >> 1)) {
// We should only shrink if the new capacity is less or at least equal to the previous_power_of_2
return;
}
// We want to shrink the queue, we will create a new queue with a smaller size
// the consumer will switch to the newer queue after emptying and deallocating the older queue
auto const nextNode = new Node{capacity, _producer->boundedQueue.hugePagesEnabled()};
// Store the new node pointer as next in the current node
_producer->next.store(nextNode, std::memory_order_release);
// Producer is now using the next node
_producer = nextNode;
}
ReadResult prepareRead() noexcept {
ReadResult readResult{_consumer->boundedQueue.prepareRead()};
if (readResult.readPos != nullptr) {
return readResult;
}
// The buffer is empty, check if another buffer exists
Node* const nextNode = _consumer->next.load(std::memory_order_acquire);
if (nextNode != nullptr) {
return readNextQueue(nextNode);
}
// Queue is empty and no new queue exists
return readResult;
}
void finishRead(std::size_t nbytes) noexcept {
_consumer->boundedQueue.finishRead(nbytes);
}
void commitRead() noexcept {
_consumer->boundedQueue.commitRead();
}
std::size_t capacity() const noexcept {
return _consumer->boundedQueue.capacity();
}
bool empty() const noexcept {
return _consumer->boundedQueue.empty() && (_consumer->next.load(std::memory_order_relaxed) == nullptr);
}
private:
// Modified by either the producer or consumer but never both
alignas(CacheLineAligned) Node* _producer{nullptr};
alignas(CacheLineAligned) Node* _consumer{nullptr};
std::uint8_t* handleFullQueue(std::size_t nbytes) noexcept {
// Then it means the queue doesn't have enough size
std::size_t capacity = _producer->boundedQueue.capacity() * 2ULL;
while (capacity < (nbytes + 1)) {
capacity = capacity * 2ULL;
}
// Apply some hard limits also on UnboundedSPSCQueue
constexpr std::size_t MaxBoundedQueueSize = 2ULL * 1024 * 1024 * 1024; // 2 GB
if DEATH_UNLIKELY(capacity > MaxBoundedQueueSize) {
DEATH_DEBUG_ASSERT(nbytes <= MaxBoundedQueueSize);
// We reached the MaxBoundedQueueSize, we won't be allocating more, instead return nullptr to block or drop
return nullptr;
}
// Commit previous write to the old queue before switching
_producer->boundedQueue.commitWrite();
// We failed to reserve because the queue was full, create a new node with a new queue
Node* nextNode = new Node{capacity, _producer->boundedQueue.hugePagesEnabled()};
// Store the new node pointer as next in the current node
_producer->next.store(nextNode, std::memory_order_release);
// Producer is now using the next node
_producer = nextNode;
// Reserve again, this time we know we will always succeed, cast to void* to ignore
std::uint8_t* const writePos = _producer->boundedQueue.prepareWrite(nbytes);
DEATH_DEBUG_ASSERT(writePos != nullptr);
return writePos;
}
ReadResult readNextQueue(Node* nextNode) noexcept {
// New buffer was added by the producer, this happens only when we have allocated a new queue
// Try the existing buffer once more
ReadResult readResult{_consumer->boundedQueue.prepareRead()};
if (readResult.readPos != nullptr) {
return readResult;
}
// Switch to the new buffer for reading commit the previous reads before deleting the queue
_consumer->boundedQueue.commitRead();
// Switch to the new buffer, existing one is deleted
std::size_t previousCapacity = _consumer->boundedQueue.capacity();
delete _consumer;
_consumer = nextNode;
readResult.readPos = _consumer->boundedQueue.prepareRead();
// We switched to a new here, so we store the capacity info to return it
readResult.allocation = true;
readResult.newCapacity = _consumer->boundedQueue.capacity();
readResult.previousCapacity = previousCapacity;
return readResult;
}
};
}
#endif
/**
@brief Stores required information about a logged entry to be dispatched to sinks
This class should not usually be used directly.
*/
struct TransitEvent
{
/** @brief Timestamp */
std::uint64_t Timestamp;
#ifndef DOXYGEN_GENERATING_OUTPUT
// Doxygen 1.12.0 cannot handle anonymous unions properly
union {
#endif
/** @brief Function name */
const char* FunctionName;
/** @brief Pointer to flush flag in case of flush event */
std::atomic<bool>* FlushFlag;
/** @brief Requested capacity in case of initialization event */
std::uint32_t Capacity;
#ifndef DOXYGEN_GENERATING_OUTPUT
};
#endif
/** @brief Message */
std::string Message;
/** @brief Trace level */
TraceLevel Level;
TransitEvent()
: Timestamp(0), FunctionName(nullptr), Level(TraceLevel::Unknown) {}
~TransitEvent() = default;
TransitEvent(TransitEvent const& other) = delete;
TransitEvent& operator=(TransitEvent const& other) = delete;
TransitEvent(TransitEvent&& other) noexcept
: Timestamp(other.Timestamp), Message(Death::move(other.Message)), FlushFlag(other.FlushFlag), Level(other.Level) {}
TransitEvent& operator=(TransitEvent&& other) noexcept {
if (this != &other) {
Timestamp = other.Timestamp;
Message = Death::move(other.Message);
FlushFlag = other.FlushFlag;
Level = other.Level;
}
return *this;
}
};
#if defined(DEATH_TRACE_ASYNC) || defined(DOXYGEN_GENERATING_OUTPUT)
/**
@brief Circular buffer for transit events
This class should not usually be used directly.
*/
class TransitEventBuffer
{
public:
explicit TransitEventBuffer(std::size_t initialCapacity)
: _capacity(Implementation::NextPowerOfTwo(initialCapacity)), _storage(std::make_unique<TransitEvent[]>(_capacity)),
_capacityMask(_capacity - 1u), _readerPos(0), _writerPos(0) {}
TransitEventBuffer(TransitEventBuffer const&) = delete;
TransitEventBuffer& operator=(TransitEventBuffer const&) = delete;
TransitEventBuffer(TransitEventBuffer&& other) noexcept
: _capacity(other._capacity), _storage(Death::move(other._storage)), _capacityMask(other._capacityMask),
_readerPos(other._readerPos), _writerPos(other._writerPos)
{
other._capacity = 0;
other._capacityMask = 0;
other._readerPos = 0;
other._writerPos = 0;
}
TransitEventBuffer& operator=(TransitEventBuffer&& other) noexcept {
if (this != &other) {
_capacity = other._capacity;
_storage = Death::move(other._storage);
_capacityMask = other._capacityMask;
_readerPos = other._readerPos;
_writerPos = other._writerPos;
other._capacity = 0;
other._capacityMask = 0;
other._readerPos = 0;
other._writerPos = 0;
}
return *this;
}
/** @brief Returns a pointer to the first transit event in the buffer, or `nullptr` if the buffer is empty */
TransitEvent* front() noexcept {
if (_readerPos == _writerPos) {
return nullptr;
}
return &_storage[_readerPos & _capacityMask];
}
/** @brief Consumes the first transit event from the buffer */
void pop_front() noexcept {
++_readerPos;
}
/** @brief Returns a pointer to the last transit event in the buffer, or expands the buffer if it is full */
TransitEvent* back() noexcept {
if (_capacity == size()) {
// Buffer is full, need to expand
expand();
}
return &_storage[_writerPos & _capacityMask];
}
/** @brief Adds a new transit event to be consumed */
void push_back() noexcept {
++_writerPos;
}
/** @brief Returns the number of unconsumed events */
std::size_t size() const noexcept {
return _writerPos - _readerPos;
}
/** @brief Returns the capacity of the buffer */
std::size_t capacity() const noexcept {
return _capacity;
}
/** @brief Returns `true` if the buffer is empty */
bool empty() const noexcept {
return _readerPos == _writerPos;
}
private:
std::size_t _capacity;
std::unique_ptr<TransitEvent[]> _storage;
std::size_t _capacityMask;
std::size_t _readerPos;
std::size_t _writerPos;
void expand() noexcept {
std::size_t newCapacity = _capacity * 2;
auto newStorage = std::make_unique<TransitEvent[]>(newCapacity);
// Move existing elements from the old storage to the new storage.
// Since the buffer is full, this moves all the previous TransitEvents, preserving their order.
// The reader position and mask are used to handle the circular buffer's wraparound.
std::size_t currentSize = size();
for (std::size_t i = 0; i < currentSize; ++i) {
newStorage[i] = Death::move(_storage[(_readerPos + i) & _capacityMask]);
}
_storage = Death::move(newStorage);
_capacity = newCapacity;
_capacityMask = _capacity - 1;
_writerPos = currentSize;
_readerPos = 0;
}
};
class LoggerBackend;
/**
@brief Stores information about the current thread and allows to receive logged entries
This class should not usually be used directly.
*/
class ThreadContext
{
friend class LoggerBackend;
private:
#ifndef DOXYGEN_GENERATING_OUTPUT
// Doxygen 1.12.0 outputs also private structs/unions even if it shouldn't
union SpscQueueUnion
{
Implementation::UnboundedSPSCQueue UnboundedSpscQueue;
Implementation::BoundedSPSCQueue BoundedSpscQueue;
SpscQueueUnion() {}
~SpscQueueUnion() {}
};
#endif
public:
ThreadContext(Implementation::QueueType queueType, std::uint32_t initialSpscQueueCapacity, bool hugesPagesEnabled)
: _threadId(format("{}", Implementation::GetNativeThreadId())), _transitEventBuffer(Implementation::TransitEventBufferInitialCapacity),
_queueType(queueType), _valid{true}, _failureCounter{0}
{
if (HasUnboundedQueueType()) {
new (&_spscQueueUnion.UnboundedSpscQueue) Implementation::UnboundedSPSCQueue{initialSpscQueueCapacity, hugesPagesEnabled};
} else if (HasBoundedQueueType()) {
new (&_spscQueueUnion.BoundedSpscQueue) Implementation::BoundedSPSCQueue{initialSpscQueueCapacity, hugesPagesEnabled};
}
}
~ThreadContext() noexcept {
if (HasUnboundedQueueType()) {
_spscQueueUnion.UnboundedSpscQueue.~UnboundedSPSCQueue();
} else if (HasBoundedQueueType()) {
_spscQueueUnion.BoundedSpscQueue.~BoundedSPSCQueueImpl();
}
}
ThreadContext(ThreadContext const&) = delete;
ThreadContext& operator=(ThreadContext const&) = delete;
#ifdef DOXYGEN_GENERATING_OUTPUT
/** @brief Returns single-producer single-consumer queue for logged entries */
Implementation::SPSCQueue& GetSpscQueue() noexcept;
#else
SpscQueueUnion const& GetSpscQueueUnion() const noexcept {
return _spscQueueUnion;
}
SpscQueueUnion& GetSpscQueueUnion() noexcept {
return _spscQueueUnion;
}
template<Implementation::QueueType queueType_>
std::conditional_t<queueType_ == Implementation::QueueType::UnboundedBlocking || queueType_ == Implementation::QueueType::UnboundedDropping,
Implementation::UnboundedSPSCQueue, Implementation::BoundedSPSCQueue>& GetSpscQueue() noexcept
{
DEATH_DEBUG_ASSERT(_queueType == queueType_);
if constexpr (queueType_ == Implementation::QueueType::UnboundedBlocking || queueType_ == Implementation::QueueType::UnboundedDropping) {
return _spscQueueUnion.UnboundedSpscQueue;
} else {
return _spscQueueUnion.BoundedSpscQueue;
}
}
template<Implementation::QueueType queueType_>
std::conditional_t<queueType_ == Implementation::QueueType::UnboundedBlocking || queueType_ == Implementation::QueueType::UnboundedDropping,
Implementation::UnboundedSPSCQueue, Implementation::BoundedSPSCQueue> const& GetSpscQueue() const noexcept
{
DEATH_DEBUG_ASSERT(_queueType == queueType_);
if constexpr (queueType_ == Implementation::QueueType::UnboundedBlocking || queueType_ == Implementation::QueueType::UnboundedDropping) {
return _spscQueueUnion.UnboundedSpscQueue;
} else {
return _spscQueueUnion.BoundedSpscQueue;
}
}
#endif
/** @brief Returns `true` if a bounded queue is used */
bool HasBoundedQueueType() const noexcept {
return (_queueType == Implementation::QueueType::BoundedBlocking) || (_queueType == Implementation::QueueType::BoundedDropping);
}
/** @brief Returns `true` if an unbounded queue is used */
bool HasUnboundedQueueType() const noexcept {
return (_queueType == Implementation::QueueType::UnboundedBlocking) || (_queueType == Implementation::QueueType::UnboundedDropping);
}
/** @brief Returns `true` if a dropping queue is used */
bool HasDroppingQueue() const noexcept {
return (_queueType == Implementation::QueueType::UnboundedDropping) || (_queueType == Implementation::QueueType::BoundedDropping);
}
/** @brief Returns `true` if a blocking queue is used */
bool HasBlockingQueue() const noexcept {
return (_queueType == Implementation::QueueType::UnboundedBlocking) || (_queueType == Implementation::QueueType::BoundedBlocking);
}
/** @brief Returns the thread ID of the current thread context */
Containers::StringView GetThreadId() const noexcept {
return _threadId;
}
/** @brief Marks the thread context as invalid */
void MarkInvalid() noexcept {
_valid.store(false, std::memory_order_relaxed);
}
/** @brief Returns `true` if the thread context is still valid */
bool IsValid() const noexcept {
return _valid.load(std::memory_order_relaxed);
}
/** @brief Increments number of failures */
void IncrementFailureCounter() noexcept {
_failureCounter.fetch_add(1, std::memory_order_relaxed);
}
/** @brief Returns the current number of failures and resets the counter */
std::size_t GetAndResetFailureCounter() noexcept {
if DEATH_LIKELY(_failureCounter.load(std::memory_order_relaxed) == 0) {
return 0;
}
return _failureCounter.exchange(0, std::memory_order_relaxed);
}
private:
SpscQueueUnion _spscQueueUnion;
Containers::String _threadId;
TransitEventBuffer _transitEventBuffer;
Implementation::QueueType _queueType;
std::atomic<bool> _valid;
alignas(Implementation::CacheLineAligned) std::atomic<std::size_t> _failureCounter;
};
/**
@brief Manages thread contexts for @ref LoggerBackend
This class should not usually be used directly.
*/
class ThreadContextManager
{
public:
/** @brief Returns static instance of thread context manager */
static ThreadContextManager& Get() noexcept;
ThreadContextManager(ThreadContextManager const&) = delete;
ThreadContextManager& operator=(ThreadContextManager const&) = delete;
/** @brief Calls the specified callback for each registered thread context */
template<typename TCallback>
void ForEachThreadContext(TCallback cb) noexcept {
std::unique_lock lock{_spinlock};
for (auto const& elem : _threadContexts) {
cb(elem.get());
}
}
/** @brief Registers a new thread context */
void RegisterThreadContext(std::shared_ptr<ThreadContext> const& threadContext) noexcept;
/** @brief Adds an invalid thread context */
void AddInvalidThreadContext() noexcept;
/** @brief Returns `true` if an invalid thread context is present */
bool HasInvalidThreadContext() const noexcept;
/** @brief Returns `true` if a new thread context is present */
bool HasNewThreadContext() noexcept;
/** @brief Removes shared invalidated thread context */
void RemoveSharedInvalidatedThreadContext(ThreadContext const* threadContext) noexcept;
private:
Containers::SmallVector<std::shared_ptr<ThreadContext>, 0> _threadContexts;
Threading::Spinlock _spinlock;
std::atomic<bool> _newThreadContextFlag{false};
std::atomic<std::uint8_t> _invalidThreadContextCount{0};
ThreadContextManager() = default;
~ThreadContextManager() = default;
};
/**
@brief Handles lifetime of the thread context
This class should not usually be used directly.
*/
class ScopedThreadContext
{
public:
ScopedThreadContext(Implementation::QueueType queueType, std::uint32_t spscQueueCapacity, bool hugePagesEnabled)
: _threadContext(std::make_shared<ThreadContext>(queueType, spscQueueCapacity, hugePagesEnabled))
{
ThreadContextManager::Get().RegisterThreadContext(_threadContext);
}
~ScopedThreadContext() noexcept {
// This destructor will get called when the thread that created this wrapper stops. We will only invalidate
// the thread context, so the backend thread will empty an invalidated ThreadContext and then remove it from
// the ThreadContextManager. Main thread is only exception for the thread who owns the ThreadContextManager.
// The thread context of the main thread can get deleted before getting invalidated
_threadContext->MarkInvalid();
// Notify the backend thread that one context has been removed
ThreadContextManager::Get().AddInvalidThreadContext();
}
ScopedThreadContext(ScopedThreadContext const&) = delete;
ScopedThreadContext& operator=(ScopedThreadContext const&) = delete;
/** @brief Returns the assigned thread context */
ThreadContext* GetThreadContext() const noexcept {
DEATH_DEBUG_ASSERT(_threadContext != nullptr);
return _threadContext.get();
}
private:
std::shared_ptr<ThreadContext> _threadContext;
};
#endif
/**
@brief Storage for deferred transit events
This class should not usually be used directly.
*/
class BacktraceStorage
{
public:
BacktraceStorage();
BacktraceStorage(std::uint32_t capacity);
/** @brief Stores the specified transit event */
void Store(TransitEvent transitEvent, Containers::StringView threadId) noexcept;
/** @brief Processes all stored transit events */
void Process(Containers::Function<void(TransitEvent const& event, Containers::StringView threadId)>&& callback) noexcept;
/** @brief Resizes the storage to the specified capacity */
void SetCapacity(std::uint32_t capacity) noexcept;
private:
#ifndef DOXYGEN_GENERATING_OUTPUT
// Doxygen 1.12.0 outputs also private structs/unions even if it shouldn't
struct StoredTransitEvent
{
StoredTransitEvent(Containers::String threadId, TransitEvent transitEvent);
Containers::String ThreadId;
TransitEvent Event;
};
#endif
std::uint32_t _capacity;
std::uint32_t _index;
Containers::SmallVector<StoredTransitEvent> _storedEvents;
};
/**
@brief Logger backend processes trace items in the background
This class should not usually be used directly.
*/
class LoggerBackend
{
public:
LoggerBackend();
~LoggerBackend();
LoggerBackend(LoggerBackend const&) = delete;
LoggerBackend& operator=(LoggerBackend const&) = delete;
/** @brief Registers the sink */
void AttachSink(ITraceSink* sink);
/** @brief Unregisters the sink */
void RemoveSink(ITraceSink* sink);
/** @brief Notifies the background worker about new entries in the queue */
void Notify() noexcept;
#if defined(DEATH_TRACE_ASYNC) || defined(DOXYGEN_GENERATING_OUTPUT)
/** @brief Returns `true` if the background worker is alive */
bool IsAlive() const noexcept;
/** @brief Returns `true` if the current thread is the background worker thread */
bool IsWorkerThread() const noexcept;
#else
/** @brief Dispatches the specified entry to all sinks */
void DispatchEntryToSinks(TraceLevel level, std::uint64_t timestamp, const void* functionName, const void* content, std::uint32_t contentLength, Containers::StringView threadId) noexcept;
/** @brief Flushes and waits until all prior entries are written to all sinks */
void FlushActiveSinks() noexcept;
#endif
/** @brief Initializes backtrace storage to be able to use @ref TraceLevel::Deferred */
void InitializeBacktrace(std::uint32_t capacity);
#if !defined(DEATH_TRACE_ASYNC)
/** @brief Writes any stored deferred entries to all sinks asynchronously */
void FlushBacktraceAsync() noexcept;
/** @brief Enqueues the specified entry to backtrace storage */
void EnqueueEntryToBacktrace(std::uint64_t timestamp, const void* functionName, const void* content, std::uint32_t contentLength) noexcept;
#endif
/** @brief Returns minimum trace level to trigger automatic flushing of deferred entries */
TraceLevel GetBacktraceFlushLevel() const noexcept;
/** @brief Sets minimum trace level to trigger automatic flushing of deferred entries */
void SetBacktraceFlushLevel(TraceLevel flushLevel) noexcept;
private:
Containers::SmallVector<ITraceSink*, 1> _sinks;
std::shared_ptr<BacktraceStorage> _backtraceStorage;
void Initialize();
void Dispose();
#if defined(DEATH_TRACE_ASYNC)
std::thread _workerThread;
Death::Threading::AutoResetEvent _wakeUpEvent;
std::atomic<TraceLevel> _backtraceFlushLevel;
std::atomic<bool> _workerThreadAlive;
Implementation::RdtscClock _rdtscClock;
Containers::SmallVector<ThreadContext*, 0> _activeThreadContextsCache;
std::chrono::system_clock::time_point _lastRdtscResyncTime;
void CleanUpBeforeExit() noexcept;
void UpdateActiveThreadContextsCache() noexcept;
void CleanUpInvalidatedThreadContexts() noexcept;
bool PopulateTransitEventFromThreadQueue(const std::uint8_t*& readPos, ThreadContext* threadContext, std::uint64_t tsNow) noexcept;
const std::uint8_t* ReadUnboundedThreadQueue(Implementation::UnboundedSPSCQueue& frontendQueue, ThreadContext* threadContext) const noexcept {
auto readResult = frontendQueue.prepareRead();
/*if (readResult.allocation) {
LOGD("Allocated new queue with capacity of {} kB (previously {} kB) from thread {}",
(readResult.newCapacity / 1024), (readResult.previousCapacity / 1024), threadContext->GetThreadId());
}*/
return readResult.readPos;
}
template<typename TThreadQueue>
std::size_t ReadAndDecodeThreadQueue(TThreadQueue& frontendQueue, ThreadContext* threadContext, std::uint64_t tsNow) noexcept {
// Note: The producer commits only complete messages to the queue.
// Therefore, if even a single byte is present in the queue, it signifies a full message.
std::size_t queueCapacity = frontendQueue.capacity();
std::size_t totalBytesRead = 0;
do {
const std::uint8_t* readPos;
if constexpr (std::is_same_v<TThreadQueue, Implementation::UnboundedSPSCQueue>) {
readPos = ReadUnboundedThreadQueue(frontendQueue, threadContext);
} else {
readPos = frontendQueue.prepareRead();
}
if (readPos == nullptr) {
// Nothing to read
break;
}
const std::uint8_t* readBegin = readPos;
if (!PopulateTransitEventFromThreadQueue(readPos, threadContext, tsNow)) {
break;
}
// Finish reading
DEATH_DEBUG_ASSERT(readPos >= readBegin, "readBuffer should be greater or equal to readBegin", 0);
std::size_t bytesRead = static_cast<std::size_t>(readPos - readBegin);
frontendQueue.finishRead(bytesRead);
totalBytesRead += bytesRead;
// Reads a maximum of one full frontend queue or the transit events' hard limit to prevent getting stuck on the same producer.
} while (totalBytesRead < queueCapacity && threadContext->_transitEventBuffer.size() < Implementation::TransitEventsHardLimit);
if (totalBytesRead != 0) {
// If we read something from the queue, we commit all the reads together at the end. This strategy
// enhances cache coherence performance by updating the shared atomic flag only once.
frontendQueue.commitRead();
}
return threadContext->_transitEventBuffer.size();
}
std::size_t PopulateTransitEventsFromFrontendQueues() noexcept;
bool HasPendingEventsForCachingWhenTransitEventBufferEmpty() noexcept;
bool CheckThreadQueuesAndCachedTransitEventsEmpty() noexcept;
void ResyncRdtscClock() noexcept;
void DispatchTransitEventToSinks(TransitEvent const& transitEvent, Containers::StringView threadId) noexcept;
void FlushActiveSinks() noexcept;
void ProcessTransitEvent(ThreadContext const& threadContext, TransitEvent& transitEvent, std::atomic<bool>*& flushFlag) noexcept;
bool ProcessLowestTimestampTransitEvent() noexcept;
void ProcessEvents() noexcept;
#else
TraceLevel _backtraceFlushLevel;
#endif
};
/**
@brief Logger enqueues trace items for processing
This class should not usually be used directly.
*/
class Logger
{
public:
Logger() {}
virtual ~Logger() = default;
Logger(Logger const&) = delete;
Logger& operator=(Logger const&) = delete;
/** @brief Registers the sink */
void AttachSink(ITraceSink* sink);
/** @brief Unregisters the sink */
void RemoveSink(ITraceSink* sink);
/** @brief Writes the specified entry to all sinks */
bool Write(TraceLevel level, const char* functionName, const char* message, std::uint32_t messageLength);
/** @brief Flushes and waits until all prior entries are written to all sinks */
void Flush(std::uint32_t sleepDurationNs = 100) noexcept;
/** @brief Initializes backtrace storage to be able to use @ref TraceLevel::Deferred */
void InitializeBacktrace(std::uint32_t capacity, TraceLevel flushLevel = TraceLevel::Unknown);
/** @brief Writes any stored deferred entries to all sinks asynchronously */
void FlushBacktraceAsync() noexcept;
#if defined(DEATH_TRACE_ASYNC) || defined(DOXYGEN_GENERATING_OUTPUT)
/** @brief Shrinks the thread-local queue to the specified target capacity */
void ShrinkThreadLocalQueue(std::size_t capacity) noexcept;
/** @brief Returns the current capacity of the thread-local queue */
std::size_t GetThreadLocalQueueCapacity() noexcept;
#endif
private:
LoggerBackend _backend;
#if defined(DEATH_TRACE_ASYNC)
static inline DEATH_THREAD_LOCAL ThreadContext* _threadContext = nullptr;
static ThreadContext* GetLocalThreadContext() noexcept;
#endif
bool EnqueueEntry(TraceLevel level, std::uint64_t timestamp, const void* functionName, const void* content, std::uint32_t contentLength) noexcept;
};
}}
#endif
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