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

From: Ingo Molnar
Date: Wed Jun 22 2005 - 17:33:13 EST

* Karim Yaghmour <karim@xxxxxxxxxxx> wrote:

> Ingo Molnar wrote:
> > the UDP-over-localhost latency was a softirq processing bug that is
> > fixed in current PREEMPT_RT patches. (real over-the-network latency was
> > never impacted, that's why it wasnt noticed before.)
> That's good to hear, but here are some random stats from the idle run:

please retest using recent (i.e. today's) -RT kernels. There were a
whole bunch of fixes that could affect these numbers. (But i'm sure you
know very well that you cannot expect a fully-preemptible kernel to have
zero runtime cost. In that sense, if you want to be fair, you should
compare it to the SMP kernel, as total preemptability is a similar
technological feat and has very similar parallelism constraints.)

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