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

[Jamie Lokier]

Miguel Freitas wrote:
> > I'm wondering what happens if the tasks are both good, early to bed
> > without a fuss.  Neither runs their entire timeslice.
> > 
> > Or to illustrate: say xine uses 10% of my CPU.  What happens when I
> > open 11 xine windows?
> 
> well of course 110% is more than what you have of resources and xine
> would have to drop frames to keep it up... :)

That's fine.  The problem is, does this completely starve the other
tasks such as kswapd, ksoftirqd, bash etc.?

The real problem is can a user accidentally or malicious lock up a box
using SCHED_SOFTRR (when xmms, xine, GNU software radio and modem are
all using it :), and also what about multi-user boxes, can two users
accidentally break it.

Perhaps there should be a _global_ maximum amount of CPU used in
SCHED_SOFTRR beyond which SCHED_SOFTRR tasks get downgraded.

-- Jamie