Re: PREEMPT_RT vs I-PIPE: the numbers, part 2

From: Lee Revell
Date: Wed Jun 22 2005 - 12:27:16 EST

On Wed, 2005-06-22 at 11:31 -0400, Karim Yaghmour wrote:
> max_ipipe_delay = 27.5us
> average_ipipe_delay = 7us
> max_preempt_delay = 55us - max_ipipe_delay = 27.5us
> average_preempt_delay = 14 us - average_ipipe_delay = 7us

Ingo, what's the status of putting irq 0 back in a thread with
PREEMPT_RT? IIRC this had some adverse (maybe unfixable?) effects so it
was disabled a few months ago.

I don't think there's much point in comparing i-pipe to PREEMPT_RT if we
know that 21usec pipeline effect from the timer IRQ (see list archives)
is still there.


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