Rough Design Switch mode between periodic tick mode & dynamic tick mode The switch trigger is when to be scheduled sched_idletd This function only works when CPU is idle If the cpu is idle, the CPU has no need to know what current time is. Scan callout queue & get next event
HZ H 2 tick mode transition after sched_idletd is scheduled time when next Timer is going to be fired Periodic tick Dynamic tick mode mode The idle process( sched_idletd ) trigger the mode transition
Current status Started to write code 11th March, 2010(JST) I implemented to scan callout queue The routine scan when the next timer event come up?
Wrapping up I started to implement tickless kernel in FreeBSD. As first step, I implemented the routine which detect when the next timer fire.
Acknowledgements Thanks Alexander Mortin Hiroki Sato for advising me !! Any idea or question?