Mentorship Session: The Ticking Beast: a Deep Dive Into Timers, Timekeeping, Tick & Tickless Kernels

Mentor: Joel Fernandes, Staff Software Engineer, Google

The Timekeeping subsystem and Timers subsystem are critical components of the Linux kernel. Its proper functioning is required for a number of critical subsystems including the Scheduler and Ftrace. This talk gives the audience a tour of the internals of these systems and the challenges that modern requirements such as power efficiency, speed of accessing a clock and dealing with clock drift present. We also go over how CPU idle affects the tick, how CPU idle affects timers, and the concept of broadcast timers.