Hi Matthew,
On 2024-12-12, "Weber (US), Matthew L" <matthew.l.weber3@xxxxxxxxxx> wrote:
> The ELISA (Linux in safety applications) foundation had a workshop
> this week with NASA and the topic of RT focused documentation came up.
> My team at Boeing is working on material to help application
> developers understand how to integrate their source code on a
> real-time Linux system.
>
> 1) Has anyone else sent a RFC with something similar that we should
> look at?
Not that I am aware of. This is also something that Linutronix has on
our roadmap as a "next step" after bringing PREEMPT_RT mainline.
> 2) We'd like to collaborate on this if anyone else is willing to
> contribute parts of the material.
Excellent!
> 3) Suggestions on how to start? Should we RFC to this list and work
> to build up a submission for the main kernel list?
I am not the one to coordinate such efforts, but RFC'ing to this list is
certainly not a bad move. Linutronix also has ideas about what such
documentation should include.
> I've CC'd you as we noticed a lot of great material from your previous
> talks/checklist on real-time.
Thank you.
> Do you mind if we use that as an outline and for some of the content?
Please do. That is why I do such talks! In particular I want to point
out my talk in 2023 about real-time application development issues:
https://www.youtube.com/watch?v=E5cTgiHJKc0
my talk from 2020 about things to consider:
https://www.youtube.com/watch?v=NrjXEaTSyrw
my blog post on the topic:
https://www.linutronix.de/blog/A-Checklist-for-Real-Time-Applications-in-Linux
and although the video was not recorded, I did a detailed (longer) talk
about building real-time applications in 2018:
https://cm.e-ale.org/2018/rt-apps/e-ale-rt-apps-SLIDES.pdf
As with all things, it really depends on the real-time requirements and
involved hardware. So the trick to the documentation will be to convey
all the details to the developer in such a way that it is understood how
the software should be implemented and why such implementations provide
real-time results under PREEMPT_RT Linux (as well as helping to choose
the necessary hardware). The documentation will not be so simple as "Do
X, Y, Z and all is good."
BTW: Linutronix is currently working on the RT monitor that was proposed
in my 2023 talk. We expect it will be quite helpful for developers new
to PREEMPT_RT. I hope we can post an initial version to LKML early next
year.
John Ogness
