Re: [patch] SCHED_SOFTRR linux scheduler policy ...

[Bill Huey (Hui) <billh@gnuppy.monkey.org>]

On Sat, Jul 12, 2003 at 08:59:18AM -0700, Davide Libenzi wrote:
> On Sat, 12 Jul 2003, Jamie Lokier wrote:
> 
> > Davide Libenzi wrote:
> > > With the current patch you do not need any special support if you are
> > > already asking for SCHED_RR policy. If you are not root you will be
> > > automatically downgraded to SCHED_SOFTRR ;)
> >
> > Cool.  What happens if you run two SCHED_SOFTRR tasks and they both
> > use 50% of the CPU - will that starve all the other tasks?  Or is the
> > CPU usage of all SOFTRR tasks bounded collectively?
> 
> Nope :) They will run their timeslice entirely and then they will try to
> get some more. Looking at their last recharge timestamp, Dad scheduler
> will put them in bed and will give other tasks a chance to run. But don't
> worry, I am very sure there're other exploit available. I just didn't have
> enough time to think about it. It is amazing how limited are things that
> you can do in one hour :)

Hey,

Have any of you folks seen this ?

	http://www.linuxdevices.com/articles/AT6078481804.html
	http://research.microsoft.com/~mbj/papers/tr-99-59_abstract.html

Neat stuff. This with a fully preemptive kernel is one of Linux kernel
dreams for multimedia.

bill