3 mechanisms on linux kernel timers

3 mechanisms on linux kernel timers

quoted from Professional Linux kernel architecture by Wolfgang Mauerer, page 908.

1. clock sources ( struct clocksource) -- form the backbone of time management. Essentially each clock source provides a monotonically increasing counter with Read Only access for the generic kernel parts.

2. Clock event devices ( struct clock_event_device ) -- Add the possibility of equipping clocks with events that occur at a certain time in the future.

3. tick devices ( struct tick_device ) -- extend clock event sources to provide a continuous stream of tick events that happen at regular time intervals. The dynamic tick mechanism allows for stopping the periodic tick during certain intervals, tough.