[Ksummit-discuss] [TECH TOPIC] Mainlining PREEMPT_RT

Christoph Lameter cl at linux.com
Wed Oct 14 11:45:31 UTC 2015


On Tue, 13 Oct 2015, Steven Rostedt wrote:

>  preempt_disable and local_irq_disable annotations

Hrm... Would there be a way to do Realtime without PREEMPT / PREEMPT_RT
and such things? Doing this performance degradation is pretty significant
and as far as I know makes this unacceptable for many uses. CONFIG_PREEMPT
is already a problem.

Or change CONFIG_PREEMPT first to be less intrusive? Have defined points
where preemption can occur like CONFIG_PREEMPT_VOLUNTARY? Could we have
realtime based on that? If we can keep the time between voluntary
preemption short enough then this should do this as well. Plus we can
likely reduce kernel complexity because code can rely on  not being
rescheduled unless an explicit call was done.



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