root/kernel/time/

[..]
  1. clockevents.c
  2. clocksource.c
  3. jiffies.c
  4. ntp.c
  5. tick-broadcast.c
  6. tick-common.c
  7. tick-internal.h
  8. tick-oneshot.c
  9. tick-sched.c
  10. timekeeping.c
  11. timer_list.c
  12. timer_stats.c
[..]