>
> *Well there's a whole rt-test suite..*
>
> *https://git.kernel.org/cgit/utils/rt-tests/rt-tests.git/
> <https://git.kernel.org/cgit/utils/rt-tests/rt-tests.git/>*
>
> * so it's gotta be good right?*
>
> * I've never compared..*


Well I was just reading the real time Linux wiki . . . man their
documentation sucks . . . But there was some claim under "how to write real
time applications" which by the way has NOTHING to do with writing RT apps
. . . and under the miscellaneous header it makes a claim that 10uS latency
should be permanent. But what it is referring to . . . your guess would be
as good as mine.

There is also a ton of hoops one needs to jump through in order to achieve
minimal latency. Booting with a USB stick for instance is said to increase
latency to 500ms, but booting without, and inserting after boot is not a
problem. Power management, and CPU on-demand CPU scaling are two thing the
BBB uses by default that are supposedly detrimental to deterministic
execution.  Probably a lot more that I'm unaware of too, but basically
anything that generates SMI's or system calls are "bad".

I think the best anyone can really hope for is to use the *rt* kernel
image, and just be aware of the rest. I'm not so sure it is a good idea to
disable power management, or one demand CPU scaling. .  .

On Thu, Sep 24, 2015 at 2:06 PM, Robert Nelson <[email protected]>
wrote:

> On Thu, Sep 24, 2015 at 3:54 PM, William Hermans <[email protected]>
> wrote:
> > Robert, so what is the real difference between RT, and non RT ? I mean I
> > know the scheduler should be faster / tighter, but has anyone bench
> marked
> > this ?
>
> Well there's a whole rt-test suite..
>
> https://git.kernel.org/cgit/utils/rt-tests/rt-tests.git/
>
> so it's gotta be good right?
>
> I've never compared..
>
> Regards,
>
> --
> Robert Nelson
> https://rcn-ee.com/
>
> --
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