IRQs: The Hard, the Soft, the Threaded and the Preemptible

Explore the intricacies of Interrupt Request (IRQ) handling in Linux systems through this comprehensive conference talk. Delve into the various types of IRQs, including hard, soft, threaded, and preemptible interrupts, and understand their roles in managing asynchronous hardware events, timekeeping, and deferred work queuing. Learn about the differences between soft IRQs and tasklets, and how they handle deferred work in the kernel. Examine the unique characteristics of the RT kernel, where hard IRQs run as preemptible threads. Gain insights into detecting IRQ scheduling problems across x86, ARM, and ARM64 architectures using tools like bpf, event tracers, and mpstat. Presented by Alison Chaiken, an experienced automotive systems programmer and kernel engineer, this talk offers valuable knowledge for Linux kernel developers and system administrators seeking to optimize interrupt handling and improve system performance.