Linked by Thom Holwerda on Thu 25th Oct 2007 07:57 UTC, submitted by JohnnyUtah
The Completely Fair Scheduler was merged for the 2.6.23 kernel. One CFS feature which did not get in, though, was the group scheduling facility. Group scheduling makes the CFS fairness algorithm operate in a hierarchical fashion: processes are divided into groups, and, within each group, processes are scheduled fairly against one another. At the higher level, each group as a whole is given a fair share of the processor. The grouping of processes is done in user space in a highly flexible manner; the control groups (formerly 'process containers') mechanism allows a management daemon to classify processes according to almost any policy.
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Member since:
2006-01-17
For single user system this'd mean that a game (run in a separate group) gets more timeslice than a backgroud daemon which is a wanted behavior, (control groups aren't merged yet though).
Also I hope it's possible to integrate something like a guaranteed timeslice mechanism (similar to MMCS on Windows) which is a useful feature for player apps (simplest form would be to reserve up to e.g. fixed % of CPU time for a process/group or similar if they want to use it). Group scheduling seems as a one way to do this, by implementing something like fixed CPU % group quota and putting apps into it.
After all, ability to give guaranteed timeslice(while taking care about time resolution as well) generally is a requirement for realtime systems.
Reminding though that Vista has huge problems with MMCS, as they seem to starve network stack, but that kind of situation is probably possible to avoid, i.e. make better implementation than their obviously rushed & unmature scheduling and/or net stack.
Edited 2007-10-25 13:45