CFS and FIFO in kernel scheduler

Question

I am new to Linux Kernel.

I am reading this informative article that says Linux kernel 2.6 is using Completly Fair Scheduling (CFS) but another related article is showing that run-queues are FIFO. Obviously there is something that has missed my attention. What is it ?

http://www.ibm.com/developerworks/linux/library/l-completely-fair-scheduler/

and

http://www.ibm.com/developerworks/linux/library/l-scheduler/

Answer 1

Did you read the 1st article you linked to? It says right there in the subheading "Providing fair access to CPUs since 2.6.23".

That is, the old O(1) scheduler was replaced by the CFS scheduler in the 2.6.23 release.