Back Completely Fair Scheduler Czech Completely Fair Scheduler German Planificador Completamente Justo Spanish زمانبند کاملاً عادلانه Persian Completely Fair Scheduler French Completely Fair Scheduler Japanese 컴플리틀리 페어 스케줄러 Korean Completely Fair Scheduler NB 完全公平排程器 Chinese
| Original author(s) | Ingo Molnár |
|---|---|
| Developer(s) | Linux kernel developers |
| Written in | C |
| Operating system | Linux kernel |
| Type | process scheduler |
| License | GPL-2.0 |
| Website | kernel |
The Completely Fair Scheduler (CFS) was a process scheduler that was merged into the 2.6.23 (October 2007) release of the Linux kernel. It was the default scheduler of the tasks of the SCHED_NORMAL class (i.e., tasks that have no real-time execution constraints) and handled CPU resource allocation for executing processes, aiming to maximize overall CPU utilization while also maximizing interactive performance.
In contrast to the previous O(1) scheduler used in older Linux 2.6 kernels, which maintained and switched run queues of active and expired tasks, the CFS scheduler implementation is based on per-CPU run queues, whose nodes are time-ordered schedulable entities that are kept sorted by red–black trees. The CFS does away with the old notion of per-priorities fixed time-slices and instead it aims at giving a fair share of CPU time to tasks (or, better, schedulable entities).[1][2]
Starting from version 6.6 of the Linux kernel, it was replaced by the EEVDF scheduler.
- ^ Love, Robert (2010). Linux Kernel Development (3rd ed.). United States of America: Addison Wesley. pp. 41–61. ISBN 9780672329463.
- ^ "Linux: The Completely Fair Scheduler | KernelTrap". 2007-04-19. Archived from the original on 2007-04-19. Retrieved 2021-05-16.