Updating the pluggable scheduler patches for the 2.6.22 kernel, Peter Williams noted, "probably the last one now that CFS is in the main line". CFS author Ingo Molnar asked, "why is CFS in mainline a problem? The CFS merge should make the life of development/test patches like plugsched conceptually easier." Peter explained, "it means a major rewrite of the plugsched interface and I'm not sure that it's worth it (if CFS works well). However, note that I did say probably not definitely :-). I'll play with it and see what happens."

Ingo went on to suggest, "most of the schedulers in plugsched should be readily adaptable to the modular scheduling-policy scheme of the upstream scheduler. I'm sure there will be some minor issues as isolation of the modules is not enforced right now - and i'd be happy to review (and potentially apply) common-sense patches that improve the framework." Peter wasn't entirely convinced, but added, "I don't feel like converting staircase and nicksched as I have no real interest in them. Perhaps I'll just create the interface and some schedulers based on my own ideas and let others such as Con and Nick add schedulers if they're still that way inclined." In response to Ingo's offer to review the work he noted, "thanks for the offer of support (it may sway my decision)".

From:	Peter Williams [email blocked]
To:	Linux Kernel Mailing List [email blocked]
Subject: [ANNOUNCE][RFC] PlugSched-6.5.1 for  2.6.22
Date:	Wed, 11 Jul 2007 15:44:25 +1000

Probably the last one now that CFS is in the main line :-(.

A patch for 2.6.22 is available at:

<http://downloads.sourceforge.net/cpuse/plugsched-6.5.1-for-2.6.22.patch;

Very Brief Documentation:

You can select a default scheduler at kernel build time.  If you wish to
boot with a scheduler other than the default it can be selected at boot
time by adding:

cpusched=<scheduler>

to the boot command line where <scheduler> is one of: ingosched,
ingo_ll, nicksched, staircase, spa_no_frills, spa_ws, spa_svr, spa_ebs
or zaphod.  If you don't change the default when you build the kernel
the default scheduler will be ingosched (which is the normal scheduler).

The scheduler in force on a running system can be determined by the
contents of:

/proc/scheduler

Control parameters for the scheduler can be read/set via files in:

/sys/cpusched/<scheduler>/

Peter
-- 
Peter Williams [email blocked]

"Learning, n. The kind of ignorance distinguishing the studious."
  -- Ambrose Bierce



From: Ingo Molnar [email blocked]
To:	Peter Williams [email blocked]
Cc:	Linux Kernel Mailing List [email blocked]
Subject: Re: [ANNOUNCE][RFC] PlugSched-6.5.1 for  2.6.22
Date:	Mon, 16 Jul 2007 10:20:25 +0200


* Peter Williams [email blocked] wrote:

> Probably the last one now that CFS is in the main line :-(.

hm, why is CFS in mainline a problem? The CFS merge should make the life 
of development/test patches like plugsched conceptually easier. (it will 
certainly cause a lot of churn, but that's for the better i think.)

Most of the schedulers in plugsched should be readily adaptable to the 
modular scheduling-policy scheme of the upstream scheduler. I'm sure 
there will be some minor issues as isolation of the modules is not 
enforced right now - and i'd be happy to review (and potentially apply) 
common-sense patches that improve the framework.

	Ingo



From:	Peter Williams [email blocked]
To:	Ingo Molnar [email blocked]
CC:	Linux Kernel Mailing List [email blocked]
Subject: Re: [ANNOUNCE][RFC] PlugSched-6.5.1 for  2.6.22
Date:	Tue, 17 Jul 2007 10:09:35 +1000

Ingo Molnar wrote:
> * Peter Williams [email blocked] wrote:
> 
>> Probably the last one now that CFS is in the main line :-(.
> 
> hm, why is CFS in mainline a problem?

It means a major rewrite of the plugsched interface and I'm not sure
that it's worth it (if CFS works well).  However, note that I did say
probably not definitely :-).  I'll play with it and see what happens.

> The CFS merge should make the life 
> of development/test patches like plugsched conceptually easier. (it will 
> certainly cause a lot of churn, but that's for the better i think.)

I don't think that is necessarily the case.

> 
> Most of the schedulers in plugsched should be readily adaptable to the 
> modular scheduling-policy scheme of the upstream scheduler.

I don't think that this necessarily true.  Ingosched and ingo_ll are
definitely out and I don't feel like converting staircase and nicksched
as I have no real interest in them.  Perhaps I'll just create the
interface and some schedulers based on my own ideas and let others such
as Con and Nick add schedulers if they're still that way inclined.

> I'm sure 
> there will be some minor issues as isolation of the modules is not 
> enforced right now - and i'd be happy to review (and potentially apply) 
> common-sense patches that improve the framework.

Thanks for the offer of support (it may sway my decision),
Peter
-- 
Peter Williams [email blocked]

"Learning, n. The kind of ignorance distinguishing the studious."
 -- Ambrose Bierce

• Archive of above thread
• KernelTrap interview with Ingo Molnar