Practical RTOS Internals
Deadlock 분석 — 4 조건·Wait-for Graph·Lock Ordering·Timeout
Coffman의 네 조건과 wait-for graph 분석, lock ordering, timeout, hierarchical locking을 살펴봅니다.
· 4분 읽기
deadlock detection
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Practical RTOS Internals
ISR-Safe API 설계 — FromISR 패턴·Higher Priority Wake·Deferred Work
FromISR API 내부 구조와 pxHigherPriorityTaskWoken, yield 결정, deferred work 패턴을 정리합니다.
· 4분 읽기
isr-safe fromisr
Practical RTOS Internals
Event Group 분석 — Bit Flag·AND/OR Wait·Sync Barrier
FreeRTOS Event Group — 24-bit flag, AND·OR semantics, clear-on-exit, multi-task sync.
· 3분 읽기
event-group bit-flag
Practical RTOS Internals
Queue 내부 구현 추적 — Ring Buffer·2 Wait Lists·Atomic Send/Receive
FreeRTOS Queue 코드 — pcWriteTo·pcReadFrom·uxMessagesWaiting + xTasksWaitingToSend/Receive.
· 3분 읽기
queue ring-buffer
Practical RTOS Internals
Priority Ceiling Protocol — Immediate vs Original 비교
PI의 대안. 각 mutex에 정적 ceiling — take 즉시 boost. Deadlock 방지.
· 4분 읽기
priority-ceiling pcp
Practical RTOS Internals
Priority Inheritance 구현 — Inherit·Disinherit·Chain
FreeRTOS PI 코드 분석 — vTaskPriorityInherit, vTaskPriorityDisinherit, chain handling.
· 4분 읽기
priority-inheritance pi
Practical RTOS Internals
Priority Inversion 문제 — Mars Pathfinder 사례·Bounded vs Unbounded
고우선 task가 저우선 task 때문에 막힘. 1997 화성 탐사선 reset의 원인.
· 4분 읽기
priority-inversion mars-pathfinder
Practical RTOS Internals
Mutex 내부 구현 추적 — Owner·Recursion Count·ISR 금지
Mutex = Semaphore + pxMutexHolder + uxBasePriority. Recursive variant는 lock-count.
· 3분 읽기
mutex owner
Practical RTOS Internals
Semaphore 내부 구현 추적 — Counter·Wait List·ISR-Safe Variant
FreeRTOS semaphore = Queue wrapper. Counter + priority-sorted wait list.
· 4분 읽기
semaphore wait-list
Practical RTOS Internals
Critical Section 구현 비교 — IRQ Disable·BASEPRI·Spinlock
3 가지 구현 — cpsid/BASEPRI mask, taskENTER_CRITICAL, SMP spinlock. Hold time이 latency 결정.
· 4분 읽기
critical-section irq-disable