Re: [RFC 8/12][PATCH] SCHED_DEADLINE: wait next instance syscalladded.

[Peter Zijlstra]

On Fri, 2009-10-16 at 17:44 +0200, Raistlin wrote:
> This commit introduces another new SCHED_DEADLINE related syscall. It is
> called sched_wait_interval() and it has close-to-clock_nanosleep semantic.
> 
> However, for SCHED_DEADLINE tasks, it should be the call with which each
> job closes its current instance. In fact, in this case, the task is put to
> sleep and, when it wakes up, the scheduler is informed that a new job
> arrived, saving the overhead that usually comes with a task activation
> to enforce maximum task bandwidth.

The changelog suggests (and a very brief looks seems to confirm) that
this code could be much smaller by using hrtimer_nanosleep().

The implementation as presented seems to only call ->wait_interval()
when the timer arms, which seems like a bug, we should always call it,
regardless of whether we're on a period boundary.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/