Tickless kernel

From Wikipedia, the free encyclopedia

A tickless kernel is an operating system kernel in which timer interrupts do not occur at regular intervals, but are only delivered as required.[1]

The Linux kernel on s390 from 2.6.6[2] and on i386 from release 2.6.21[3] can be configured to turn the timer tick off (tickless or dynamic tick) for idle CPUs using CONFIG_NO_HZ, and from 3.10 with CONFIG_NO_HZ_IDLE extended for non-idle processors with CONFIG_NO_HZ_FULL.[4] The XNU kernel in Mac OS X 10.4 on, and the NT kernel in Windows 8 on, are also tickless.[1] The Solaris 8 kernel introduced the cyclic subsystem which allows arbitrary resolution timers and tickless operation.[5] FreeBSD 9 introduced a "dynamic tick mode" (aka tickless).[6]

As of 2020, there is a plan to add this to MINIX 3[7] in the medium term.[8]


  1. ^ a b Bright, Peter (October 28, 2012). "Better on the inside: under the hood of Windows 8". Ars Technica. section "Tick tock".
  2. ^ "Linux 2.6.6-rc3". Lwn.net. Retrieved 2015-04-09.
  3. ^ "Clockevents and dyntick". Lwn.net. 2007-02-21. Retrieved 2015-04-09.
  4. ^ "(Nearly) full tickless operation in 3.10". Lwn.net. Retrieved 2015-04-09.
  5. ^ "Bryan Cantrill (former Solaris kernel engineer) comment". Retrieved 2017-01-07..
  6. ^ "What's cooking for FreeBSD 9?".
  7. ^ "Tickless Kernel". Retrieved 25 February 2020.
  8. ^ "The MINIX 3 Road Map". Retrieved 25 February 2020.