starting a new trail for a pi3b.

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starting a new trail for a pi3b.

Gene Heskett-4
Greetings all;

I found the u-sd card with a debian-arm buster net-install on it.  And I
generally like what I see. Then I noticed there was a newer kernel
marked preempt-rt. What the hell, give it a shot, and installed it along
with the mesa-utils pkgs.

rebooted, runs fine. Ran glxgears full screen, getting about 9 fps.
Nowhere near the 27 fps I get out of a raspian buster install, but is
still around 7.5 fps faster than jessie or stretch gave me, a quite
worthwhile improvement.

So, over the next week I'll setup a build environment on a plugged in ssd
and see if I can build an arm64, deb format version of linuxcnc. That
would be a good sized feather in my hat!

Cheers, Gene Heskett
--
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page <http://geneslinuxbox.net:6309/gene>

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Re: starting a new trail for a pi3b.

Étienne Mollier
Gene, on 2019-08-30:

> I found the u-sd card with a debian-arm buster net-install on it.  And I
> generally like what I see. Then I noticed there was a newer kernel
> marked preempt-rt. What the hell, give it a shot, and installed it along
> with the mesa-utils pkgs.
>
> rebooted, runs fine. Ran glxgears full screen, getting about 9 fps.
> Nowhere near the 27 fps I get out of a raspian buster install, but is
> still around 7.5 fps faster than jessie or stretch gave me, a quite
> worthwhile improvement.
>
> So, over the next week I'll setup a build environment on a plugged in ssd
> and see if I can build an arm64, deb format version of linuxcnc.  That
> would be a good sized feather in my hat!

Good day Gene,

It sounds good; let us know how things evolve.  :)

If the end result is not satisfactory, I vaguely recalled my
school days, which are actually pretty nearby from today, and my
course on Real-Time Operating Systems.  Various kernels and
systems have been mentioned, notably:

  - RTAI (you mentioned that in another thread),

  - QNX (I don't suppose you are willing to spend hundreds of
    thousands on that one, but it was pretty neat in the past),

  - Xenomai (this was the main RT engine of the course).


I see Xenomai was part of Debian at some point, but the package
is currently orphaned:

        https://packages.debian.org/search?searchon=sourcenames&keywords=xenomai

Upstream, the project seems still running:

        https://www.xenomai.org/

I guess you might want to start here:

        https://gitlab.denx.de/Xenomai/xenomai/wikis/Start_Here

Browsing a bit on their wiki, they advertise being compatible
with your Pi 3B (it's in the liste of "Supported Evaluation
Boards"):

        https://gitlab.denx.de/Xenomai/xenomai/wikis/Supported_Hardware#arm


Of course, this advice comes from a guy who thinks CPU cycles
should be reserved for scientific computations, not doing kernel
mode stuff juggling with tasks.  So, take this with a gentle
grain of salt.  ;)

Have you had the occasion to consider Xenomai in the past ?
Do you think it could be compatible with your CNC toolset ?


> Cheers, Gene Heskett

Happy hacking and kind regards,
--
Étienne Mollier <[hidden email]>
Fingerprint:  5ab1 4edf 63bb ccff 8b54  2fa9 59da 56fe fff3 882d



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