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

Ingo Molnar
2005-06-23T00:09:56Z

* Karim Yaghmour <karim@opersys.com> wrote:

> Ingo Molnar wrote:
> > please retest using recent (i.e. today's) -RT kernels. There were a
> > whole bunch of fixes that could affect these numbers.
>
> At this point, we're bound to rerun some of the tests. But there's
> only so many times that one can claim that such and such test isn't
> good enough because it doesn't have all the latest bells and whistles.
> Surely there's more to this overhead than just rudimentary bugfixes.

well, it was your choice to benchmark ADEOS against PREEMPT_RT, right?
You posted numbers that showed your project in a favorable light while
the PREEMPT_RT numbers were more than 100% off. Your second batch of
numbers showed a tie, but we still dont know the true correct PREEMPT_RT
irq latency values on your hardware, because your testing still had
bugs. So a minimum requirement would be to post accurate numbers - you
have started this after all.

this thread showcases one of the many reasons why 'vendor sponsored
benchmarking' is such a bad idea. I wont post benchmark numbers
comparing PREEMPT_RT to 'other' realtime projects. I'm obviously biased,
everyone else sees me as biased, so what's the point? Should i pretend
i'm not biased towards the stuff i wrote? That would be hypocritical
beyond recognition. I dont benchmark PREEMPT_RT against other projects
because i know it perfectly well that it is the best thing since sliced
bread ;)

Ingo