Part 4: Synchronization and Inter-Thread Communication
This section covers kernel objects for thread synchronization and data passing in detail.
What You’ll Learn
- Mutexes for mutual exclusion
- Semaphores for signaling and counting
- Condition variables for complex synchronization
- Spinlocks and atomic operations
- Message queues, FIFOs, LIFOs
- Pipes and mailboxes
- Events and polling
- Zbus publish-subscribe messaging
Chapters
| Chapter | Description |
|---|---|
| Mutexes | Mutual exclusion and priority inheritance |
| Semaphores | Counting and binary semaphores |
| Condition Variables | Wait with predicate pattern |
| Spinlocks | ISR-safe locking and atomics |
| Message Queues | Fixed-size message passing |
| FIFOs and LIFOs | Variable-size data passing |
| Pipes and Mailboxes | Byte streams and sync messaging |
| Events and Polling | Multi-event waiting |
| IPC Selection Guide | Decision flowcharts |
| Zbus | Publish-subscribe message bus |
When to Use What
flowchart TD
A[Need to communicate?] --> B{Protect shared data?}
B -->|Yes| C{ISR context?}
B -->|No| D{Pass data?}
C -->|Yes| E[Spinlock]
C -->|No| F[Mutex]
D -->|Yes| G{Fixed size?}
D -->|No| H{Signal event?}
G -->|Yes| I[Message Queue]
G -->|No| J[FIFO/LIFO]
H -->|Yes| K[Semaphore/Events]
H -->|No| L[Condition Variable]
Choosing the right synchronization primitive is crucial for correctness and performance.