Re: [PATCH 01/13] sched: Add 3 new scheduler syscalls to support anextended scheduling parameters ABI

From: Steven Rostedt
Date: Tue Jan 21 2014 - 11:03:10 EST


On Tue, 21 Jan 2014 16:46:03 +0100
Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:

> On Tue, Jan 21, 2014 at 04:38:51PM +0100, Peter Zijlstra wrote:
> > SCHED_DEADLINE: Sporadic task model deadline scheduling
> > SCHED_DEADLINE is an implementation of GEDF (Global Earliest
> > Deadline First) with additional CBS (Constant Bandwidth Server).
>
> We might want to re-word that to:
>
> SCHED_DEADLINE currently is an implementation of GEDF, however
> any policy that correctly schedules the sporadic task model is
> a valid implementation.
>
> To make sure we should not rely on the actual implementation; there's
> many possible algorithms to schedule the sporadic task model.

Probably should post some links to GEDF documentation too?

-- Steve

>
> > The CBS guarantees that tasks that over-run their specified
> > budget are throttled and do not affect the correct performance
> > of other SCHED_DEADLINE tasks.
> >
> > SCHED_DEADLINE tasks will fail FORK(2) with -EAGAIN
> >
> > Setting SCHED_DEADLINE can fail with -EINVAL when admission
> > control tests fail.
> >

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