MACOS TIPS FOR PROGRAMMERS: THREADING

Summary from the TLDR Web Dev newsletter

Apple's system aggressively prioritizes tasks based on Quality of Service (QoS) classes (User Interactive, User Initiated, Legacy, Utility, and Background). This influences CPU scheduling and I/O. To avoid priority inversion bugs, use specific synchronization primitives like `os_unfair_lock` or `pthread_mutex`, which enable QoS inheritance, boosting lower-priority threads when accessed by higher-priority ones.