Day 24 - Polling / IRQ Hybrid Model¶
Summary¶
Implemented a hybrid update mechanism combining:
- IRQ-based updates
- Polling-based fallback
- On-demand read
What I Learned¶
- How to design hybrid update systems
- Trade-offs between latency and reliability
- Safe workqueue scheduling patterns
- How to design sysfs as control interface
- Importance of runtime observability
Key Concepts¶
- IRQ provides low-latency updates
- Polling ensures data consistency
- Hybrid model balances both
Challenges¶
- Avoiding deadlock between mutex and workqueue
- Handling enable/disable transitions safely
- Designing clean update flow
Debugging Experience¶
Used:
to observe:
- update source
- timing behavior
- event counters
Takeaways¶
- Not all race conditions need to be eliminated
- Linux kernel design prefers eventual consistency
- Observability is critical for debugging
- Separation of control and execution is important
Next Steps¶
- Add rate limiting for polling
- Improve IRQ handling robustness
- Explore state machine design