<p dir="ltr"><br>
On Feb 9, 2014 12:30 PM, "John Morris" <<a href="mailto:john@zultron.com">john@zultron.com</a>> wrote:<br>
><br>
> On 02/09/2014 06:27 AM, Sandro Mani wrote:<br>
> ><br>
> > On 09.02.2014 09:16, John Morris wrote:<br>
> >> My goal for the forthcoming LinuxCNC release is readiness for inclusion<br>
> >> in both Fedora and Debian.<br>
> >><br>
> > Wow exciting, thanks! How are you planning to deal with the realtime<br>
> > kernel requirement, or is that beyond the scope of your work?<br>
><br>
> The meat of the last year-plus effort was introducing support for the<br>
> PREEMPT_RT and Xenomai RT kernels, and teaching it to build<br>
> run-time-selectable modules for all supported thread flavors in one<br>
> "./configure && make" run.<br>
><br>
> Since PREEMPT_RT has no special build requirements, those RT modules are<br>
> built and packaged by default, so I hope to 'sneak' them into Fedora,<br>
> despite lack of in-distro support. You may then "bring your own" RT<br>
> kernel from e.g. MRG or Planet CCRMA to get hard RT behavior; otherwise,<br>
> the POSIX "simulator" threads work with no special kernel requirements<br>
> (but all bets off as far as latency requirements).<br>
><br>
> For those requiring even tighter latency than PREEMPT_RT for e.g.<br>
> software stepper motor drivers, a 3rd-party repo can supply the Xenomai<br>
> kernel, run-time libs, and matching LinuxCNC RT modules.<br>
><br>
> RTAI kernel support could be offered in the same way, but for a number<br>
> of reasons, many (but not all) of us think of RTAI support as deprecated.<br>
><br>
> For more info, here's a short paper presented at last year's OSADL Real<br>
> Time Linux Workshop:<br>
><br>
> <a href="http://static.mah.priv.at/public/paper.pdf">http://static.mah.priv.at/public/paper.pdf</a><br>
><br>
> Sadly, Debian has beat out the Fedora project by getting an RT kernel<br>
> into the main repo, just the latest reason I continue finding myself<br>
> alone running Red Hat-derivative distros among CAD/CAM/CNC/Maker/3D<br>
> printer circles. I'm considering launching a campaign in the Fedora<br>
> community to raise attention these issues, but don't yet know where to<br>
> begin. I heard previous inquiries were shut down hard, but maybe the<br>
> context has changed since the last time.<br>
><br>
> John<br>
> --<br>
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<p dir="ltr">With regards to bringing these issues to Fedora's attention I'd suggest targeting the mrg folks first. That product represents RH's interest in rt and that's your best bet for providing justification for why such an addition is a good idea.</p>