Namespaces
	Queue

Classes
struct	LocklessAtomicLockFree
	compile-time lock-free possibility for an atomic of unsigned integral width WIDTH More...

class	LocklessPriorityQueue
	lockless ISR-safe priority queue implementation for Os::QueueInterface More...

struct	LocklessPriorityQueueHandle
	handle for the lockless priority queue More...

struct	LocklessSlot
	per-slot data for the lockless priority queue More...

class	PriorityMemQueue
	AtomicQueue-based priority queue implementation. More...

struct	PriorityMemQueueHandle
	critical data stored for priority queue More...

class	PriorityQueue
	generic priority queue implementation More...

struct	PriorityQueueHandle
	critical data stored for priority queue More...

struct	UsedTotal
	Generic used/total struct. More...

Typedefs
using	LocklessStateTagType = U64

Enumerations
enum	LocklessSlotState : LocklessStateTagType { LOCKLESS_SLOT_FREE = 0, LOCKLESS_SLOT_WRITING = 1, LOCKLESS_SLOT_READY = 2, LOCKLESS_SLOT_READING = 3 }
	slot lifecycle states for the lockless priority queue More...

enum	Status { OP_OK, ERROR }
	Generic OK/ERROR status. More...

Functions
static constexpr U32	priorityBitMask (FwQueuePriorityType priority)
	Get the bit mask for a priority. More...

static I32	findMSB (U32 value)
	Find most significant bit set (IPC-style priority finding) More...

static void	validateQueueConfigs (PriorityMemQueue::QueueConfig *queueConfigs, FwSizeType numQueueConfigs)
	Validate queue configuration structures. More...

static Types::AtomicQueue *	resolvePriorityQueue (PriorityMemQueueHandle &handle, FwQueuePriorityType &priority, FwEnumStoreType queueId, bool requirePrioritySizing)
	Resolve priority to a valid AtomicQueue, fallback to DEFAULT if needed. More...

static void	updateHighWaterMark (std::atomic< U32 > *highWaterMarks, FwSizeType index, U32 currentDepth, FwEnumStoreType queueId)
	Update per-priority high water mark atomically. More...

Variables
constexpr U32	LOCKLESS_QUEUE_BLOCKING_BACKOFF_US = 100

constexpr FwSizeType	LOCKLESS_QUEUE_SLOT_ALIGNMENT = 64

constexpr FwSizeType	LOCKLESS_QUEUE_MAX_RETRY_PASSES = 4

constexpr U32	LOOP_GUARD_LIMIT = 2000

Typedef Documentation

◆ LocklessStateTagType

typedef U64 Os::Generic::LocklessStateTagType

Unsigned integral type of the lockless queue slot state-tag word. The low STATE_BITS hold the slot state; the remaining bits hold the ABA epoch tag. std::atomic of this type must be lock-free on the target platform (never-lock-free widths are rejected at compile time; the authoritative check is runtime-asserted at create()). Platforms without lock-free 64-bit atomics may configure a narrower type (U32, U16, or U8), shrinking the ABA tag by the same amount (62, 30, 14, or 6 tag bits respectively; see SDD sections 4 and 15 for the wrap consequence and a WARNING on the narrow-tag ordering risk).

Definition at line 26 of file LocklessQueueCfg.hpp.

Enumeration Type Documentation

◆ LocklessSlotState

enum Os::Generic::LocklessSlotState : LocklessStateTagType

slot lifecycle states for the lockless priority queue

Each slot in the queue moves through a four-state state machine. Producers transition slots FREE -> WRITING -> READY. Consumers transition slots READY -> READING -> FREE. State values occupy the low bits of a packed atomic; the remaining bits are used as an ABA tag.

Enumerator
LOCKLESS_SLOT_FREE	slot contains no data; available to a producer
LOCKLESS_SLOT_WRITING	producer has reserved the slot and is filling it
LOCKLESS_SLOT_READY	slot contains a published message available to a consumer
LOCKLESS_SLOT_READING	consumer has reserved the slot and is draining it

Definition at line 59 of file LocklessPriorityQueue.hpp.

◆ Status

enum Os::Generic::Status

Generic OK/ERROR status.

Enumerator
OP_OK	Operation succeeded.
ERROR	Operation failed.

Definition at line 26 of file Os.hpp.

Function Documentation

◆ findMSB()

static I32 Os::Generic::findMSB ( U32 value )

inlinestatic

Find most significant bit set (IPC-style priority finding)

Parameters

value bit mask to search

Returns: bit position of MSB, or -1 if no bits set

Definition at line 190 of file PriorityMemQueue.cpp.

◆ priorityBitMask()

static constexpr U32 Os::Generic::priorityBitMask ( FwQueuePriorityType priority )

static

Get the bit mask for a priority.

Parameters

priority priority to get mask for

Returns: bit mask with the priority bit set

Definition at line 54 of file PriorityMemQueue.cpp.

◆ resolvePriorityQueue()

static Types::AtomicQueue* Os::Generic::resolvePriorityQueue	(	PriorityMemQueueHandle &	handle,
		FwQueuePriorityType &	priority,
		FwEnumStoreType	queueId,
		bool	requirePrioritySizing
	)

static

Resolve priority to a valid AtomicQueue, fallback to DEFAULT if needed.

Parameters

handle	queue handle
priority	input/output priority (may be modified to DEFAULT)
queueId	queue ID for assertions
requirePrioritySizing	whether to assert on fallback

Returns: pointer to AtomicQueue or nullptr if uninitialized

Definition at line 591 of file PriorityMemQueue.cpp.

◆ updateHighWaterMark()

static void Os::Generic::updateHighWaterMark	(	std::atomic< U32 > *	highWaterMarks,
		FwSizeType	index,
		U32	currentDepth,
		FwEnumStoreType	queueId
	)

static

Update per-priority high water mark atomically.

Parameters

highWaterMarks	array of HWM atomics
index	array index (not priority value)
currentDepth	current queue depth
queueId	queue ID for assertions

Definition at line 621 of file PriorityMemQueue.cpp.

◆ validateQueueConfigs()

static void Os::Generic::validateQueueConfigs	(	PriorityMemQueue::QueueConfig *	queueConfigs,
		FwSizeType	numQueueConfigs
	)

static

Validate queue configuration structures.

Parameters

queueConfigs	array of queue configurations to validate
numQueueConfigs	number of configurations

Definition at line 258 of file PriorityMemQueue.cpp.

Variable Documentation

◆ LOCKLESS_QUEUE_BLOCKING_BACKOFF_US

constexpr U32 Os::Generic::LOCKLESS_QUEUE_BLOCKING_BACKOFF_US = 100

Backoff (microseconds) between bounded scans on the BLOCKING send/receive paths. Shorter values lower message latency; longer values lower idle CPU use of blocked threads. Must be greater than 0: a zero backoff could livelock on a strict-priority scheduler.

Definition at line 31 of file LocklessQueueCfg.hpp.

◆ LOCKLESS_QUEUE_MAX_RETRY_PASSES

constexpr FwSizeType Os::Generic::LOCKLESS_QUEUE_MAX_RETRY_PASSES = 4

Retry passes through the slot array before a NONBLOCKING operation returns FULL/EMPTY. Larger values reduce spurious FULL/EMPTY under contention at the cost of a larger bound on non-blocking call time (depth * passes).

Definition at line 41 of file LocklessQueueCfg.hpp.

◆ LOCKLESS_QUEUE_SLOT_ALIGNMENT

constexpr FwSizeType Os::Generic::LOCKLESS_QUEUE_SLOT_ALIGNMENT = 64

Alignment (bytes) of each queue slot. Set to the target's cache-line size (typically 64) to avoid false sharing between adjacent slots under contention; smaller power-of-two values reduce memory use on constrained targets.

Definition at line 36 of file LocklessQueueCfg.hpp.

◆ LOOP_GUARD_LIMIT

constexpr U32 Os::Generic::LOOP_GUARD_LIMIT = 2000

Definition at line 26 of file PriorityMemQueue.cpp.

Namespaces

Classes

Typedefs

Enumerations

Functions

Variables

Typedef Documentation

◆ LocklessStateTagType

Enumeration Type Documentation

◆ LocklessSlotState

◆ Status

Function Documentation

◆ findMSB()

◆ priorityBitMask()

◆ resolvePriorityQueue()

◆ updateHighWaterMark()

◆ validateQueueConfigs()

Variable Documentation

◆ LOCKLESS_QUEUE_BLOCKING_BACKOFF_US

◆ LOCKLESS_QUEUE_MAX_RETRY_PASSES

◆ LOCKLESS_QUEUE_SLOT_ALIGNMENT

◆ LOOP_GUARD_LIMIT