Re: [RFC][PATCH 02/22] sched: add extended scheduling interface

From: Steven Rostedt
Date: Fri Nov 12 2010 - 14:21:46 EST


On Fri, 2010-11-12 at 18:42 +0100, Tommaso Cucinotta wrote:
> Il 12/11/2010 17:38, Steven Rostedt ha scritto:
> > A while ago I implemented an EDF scheduler for a client (before working
> > with Red Hat), and one thing they asked about was having a "soft group",
> > which was basically: This group is guaranteed X runtime in Y period, but
> > if the system is idle, let the group run, even if it has exhausted its X
> > runtime.
> >
> > Is this supported?
> Actually, I know that Dario has an implementation of exactly this
> feature (and it used to be implemented in our previous scheduler as
> well, i.e., the old AQuoSA stuff):
> a per-task flag, when enabled, allows to put temporarily the task into
> SCHED_OTHER when its budget is exhausted. Therefore, it will be allowed
> to run for more than its budget but without breaking the temporal
> isolation with the other SCHED_DEADLINE tasks. Furthermore, it won't
> starve other SCHED_OTHER tasks, as it will compete with them for the CPU
> during the budget-exhausted time windows.

Good to know, thanks!

-- Steve


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