Linked by Thom Holwerda on Sun 22nd Apr 2007 22:47 UTC
Linux Ingo Molnar released a new patchset titled the 'Modular Scheduler Core and Completely Fair Scheduler'. He explained, "this project is a complete rewrite of the Linux task scheduler. My goal is to address various feature requests and to fix deficiencies in the vanilla scheduler that were suggested/found in the past few years, both for desktop scheduling and for server scheduling workloads."
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by hornett on Mon 23rd Apr 2007 15:01 UTC
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I'm running v5 of the new scheduler, it seems very good indeed.

I noticed that after patching the kernel, there was an option in menuconfig for automatically renicing X to -19.

I didn't see anything specifically about it on Ingo's readme, but there is a bit about the niceness handling in general:

the CFS scheduler has a much stronger handling of nice levels and SCHED_BATCH: both types of workloads should be isolated much more agressively than under the vanilla scheduler.

I wonder if we might see a return to the times of distributions renicing X by default to make it more responsive if this sched becomes the default...

For those who are curious to try the patch, it is available from:

Reply Score: 3

RE: Sched_Fair
by RJop on Mon 23rd Apr 2007 15:31 in reply to "Sched_Fair"
RJop Member since:

> I wonder if we might see a return to the times of
> distributions renicing X by default to make it more
> responsive if this sched becomes the default...

CFS has not been selected to next Linux scheduler yet. There's couple of others also which "compete" that title. For example I don't think that Con's SD needs X's renicing.

Edit: And Linus really hates X renising so I'm pretty sure that next scheduler won't do it.
"... renicing X is the *WRONG*THING*TO*DO*. Just don't do it. It's wrong. It was wrong with the old schedulers, it's wrong with the new scheduler, it's just WRONG." - Linus Torvalds

Edited 2007-04-23 15:36

Reply Parent Score: 3

RE[2]: Sched_Fair
by hornett on Mon 23rd Apr 2007 15:58 in reply to "RE: Sched_Fair"
hornett Member since:

Indeed, that was exactly my point.

Hence my question, also *if* this scheduler becomes default, would Linus et al, change their position on renicing X if it is beneficial to interactivity?

Is there some underlying reason why X should not be treated as a special case if it useful to ensure it can run when it needs to?

Reply Parent Score: 1

RE: Sched_Fair
by smitty on Mon 23rd Apr 2007 21:23 in reply to "Sched_Fair"
smitty Member since:

There was just a discussion about that very feature.

Reply Parent Score: 2

RE[2]: Sched_Fair
by rhyotte on Tue 24th Apr 2007 05:10 in reply to "Sched_Fair"
rhyotte Member since:

Im not sure if posting from a mailing list without explicit permission is ok. So I will simply say that RJop's post is a direct snipped of a LONG thread. Ingo and Linus have been going back and forth on this X renice issue. At this particular moment in time Ingo is basicly stating ...that I really do have a plan and just please check this out Linus... ( thats a very very very loose semi paraphrase not at all a quote ) he goes on to explain that everything in CFS is "Economy driven" every thing is held accountable ect. I wont try to loosely explain further at the moment. I will say that the information can be found on the Con Kolivas CK mailing list. So far both SD and CFS are looking pretty interesting Ingo is a pretty sharp programmer as most folks know. Con however is also pretty sharp and his SD scheduler is keeping Ingo somewhat on his toes! End result is that it dont matter which approach wins, we the people definitely will benefit largely as both are already in GOOD shape.


Edited 2007-04-24 05:13

Reply Parent Score: 1