Re: [RFC] CPU controllers?

[Nick Piggin]

Srivatsa Vaddagiri wrote:
> On Sat, Jun 17, 2006 at 06:48:17PM +1000, Nick Piggin wrote:
>
> > Srivatsa Vaddagiri wrote:
> >
> > > 	- Do we need mechanisms to control CPU usage of tasks, further to 
> > > 	what
> > > 	  already exists (like nice)?  IMO yes.
> >
> > Can we get back to the question of need? And from there, work out what
> > features are wanted.
> >
> > IMHO, having containers try to virtualise all resources (memory, pagecache,
> > slab cache, CPU, disk/network IO...) seems insane: we may just as well use
> > virtualisation.
> >
> > So, from my POV, I would like to be convinced of the need for this first.
> > I would really love to be able to keep core kernel simple and fast even if
> > it means edge cases might need to use a slightly different solution.
>
>
> I think a proportional-share scheduler (which is what a CPU controller
> may provide) has non-container uses also. Do you think nice (or sched policy) 
> is enough to, say, provide guaranteed CPU usage for applications or limit 
> their CPU usage? Moreover it is more flexible if guarantee/limit can be 
> specified for a group of tasks, rather than individual tasks even in
> non-container scenarios (like limiting CPU usage of all web-server 
> tasks togther or for limiting CPU usage of make -j command).

Oh, I'm sure there are lots of things we *could* do that we currently can't.

What I want to establish first is: what exact functionality is required, why,
and by whom. Only then can we sanely discuss the fitness of solutions and
propose alternatives, and decide whether to merge.

--
SUSE Labs, Novell Inc.
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