Re: RFC for a new Scheduling policy/class in the Linux-kernel

[Peter Zijlstra]

On Mon, 2009-07-13 at 17:44 +0200, Raistlin wrote:
> > PIP doesn't suffer this, but does suffer the pain from having to
> > reimplement the full schedule function on the waitqueues, which when you
> > have hierarchical scheduling means you have to replicate the full
> > hierarchy per waitqueue.
> > 
> And, further than this, at least from my point of view, if you have
> server/group based scheduling, and in general some kind of budgeting or
> bandwidth enforcing mechanism in place, PIP is far from being a
> solution...

I think you can extend PIP to include things like bandwidth inheritance
too. Instead of simply propagating the priority through the waitqueue
hierarchy, you can pass the actual task around, and having this task you
can indeed consume its bandwidth etc..

But sure, hierarchical scheduling and things really complicate the
waitqueue implementation.

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