Linux BSP Practical Course (Time Driven Chapter): Timing Function of Time Subsystem

• Time subsystem architecture

• Initialization of timers and clock sources

• Initialization of local timer

• Initialization of system counter

• High resolution timer hrtimer

• Initialization of hrtimer

• Use of hrtimer

• Low resolution timer

• sched_timer

If the kernel is alive, then time is the heart of the kernel, controlling the pulse of the kernel, but the way this heart beats will be different depending on the hardware configuration. There are a lot of requirements in the kernel that require the help of time, such as timers, process scheduling, time acquisition , etc. The time subsystem in the kernel is used to implement this part of the function.

Time subsystem architecture

The Linux time subsystem functionally divides the above requirements into timing and timing . Timing is used to trigger interrupt events at regular intervals, while timing is used to record the timeline of the real world. The schematic diagram of its software architecture is as follows: