Re: RFC: THE OFFLINE SCHEDULER

Ingo Molnar
2009-08-26T18:05:34Z

* Christoph Lameter <cl@linux-foundation.org> wrote:

> On Wed, 26 Aug 2009, Peter Zijlstra wrote:
>
> > On Wed, 2009-08-26 at 11:41 -0400, Christoph Lameter wrote:
> > > On Wed, 26 Aug 2009, Peter Zijlstra wrote:
> > >
> > > > Why waste a whole cpu for something that could be done by part of one?
> > >
> > > Because of latency and performance requirements
> >
> > Latency is the only one, and yes people have been using hacks
> > like this, I've also earlier mentioned RTAI, RTLinux and
> > L4-Linux which basically do the same thing.
> >
> > The problem is, that its not linux, you cannot run something on
> > a these off-cores and use the same functionality as linux, if
> > you could it'd not be offline.
>
> Right. We discussed this. Why are you repeating the same old
> arguments?

The thing is, you have cut out (and have not replied to) this
crutial bit of what Peter wrote:

> > The past year or so you've been whining about the tick latency,
> > and I've seen exactly _0_ patches from you slimming down the
> > work done in there, even though I pointed out some obvious
> > things that could be done.

... which pretty much settles the issue as far as i'm concerned. If
you were truly interested in a constructive solution to lower
latencies in Linux you should have sent patches already for the low
hanging fruits Peter pointed out.

Ingo