Re: [RFC][PATCH 02/11] sched: SCHED_DEADLINE policy implementation.

[Peter Zijlstra]

On Sun, 2010-02-28 at 20:17 +0100, Raistlin wrote:
> +/*
> + * Pure Earliest Deadline First (EDF) scheduling does not deal with the
> + * possibility of a task lasting more than what it declared, and thus
> + * exhausting its runtime.
> + *
> + * Here we are interested in making runtime overrun possible, but we do
> + * not want a task which is misbehaving to affect the scheduling of all
> + * other tasks.
> + * Therefore, a budgeting strategy called Constant Bandwidth Server (CBS)
> + * is used, in order to confine each task within its own bandwidth.
> + *
> + * This function deals exactly with that, and ensures that when the runtime
> + * of a task is replenished, its deadline is also postponed. That results
> + * in "priority unboosting" for the overrunning task, and makes it impossible
> + * for it to cause unexpected interfere to other tasks in the system.
> + */ 

This is not about lock/inheritance related overrun, right? But simply a
task that got its WCET wrong.


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