Re: [PATCH 03/14] sched: SCHED_DEADLINE structures & implementation.

[Peter Zijlstra]

On Mon, Oct 14, 2013 at 12:43:35PM +0200, Juri Lelli wrote:
> +static void update_curr_dl(struct rq *rq)
> +{
> +	struct task_struct *curr = rq->curr;
> +	struct sched_dl_entity *dl_se = &curr->dl;
> +	u64 delta_exec;
> +
> +	if (!dl_task(curr) || !on_dl_rq(dl_se))
> +		return;
> +
> +	/*
> +	 * Consumed budget is computed considering the time as
> +	 * observed by schedulable tasks (excluding time spent
> +	 * in hardirq context, etc.)
> +	 */
> +	delta_exec = rq->clock_task - curr->se.exec_start;

Oh, cute.. So we compute deadlines from rq->clock but compute runtime
from rq->clock_task.

So won't that give funny results in that clock_task is generally slower
than clock; so people get more 'time'.

Maybe there's some illumination on this point further on; I'll continue
reading.
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