Re: [patch] Real-Time Preemption, -RT-2.6.12-rc6-V0.7.48-00

[Ingo Molnar]

* Gene Heskett <gene.heskett@xxxxxxxxxxx> wrote:

> Glitch reports as they develop of course.
> 
> Q: Whats the diff between turning on hardirq's in mode 3, and mode 4?

well, "mode 3" is PREEMPT_DESKTOP - normal CONFIG_PREEMPT on the 
mainstream kernel. If you turn on hardirq/softirq threading then you can 
e.g. chprio your sound IRQ to have better audio latencies. It will cause 
runtime overhead though. On "mode 4" (PREEMPT_RT) hardirq/softirq 
threading is mandatory (due to the processing model).

	Ingo
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