https://www.zdnet.com/article/20-years-later-real-time-linux...
This article explains well why PREEMPT_RT is a big deal and why it was so much work to get in into the kernel.
Recent discussion:
Real-time Linux is officially part of the kernel (arstechnica.com) | 500 points | 139 comments | 10 days ago | https://news.ycombinator.com/item?id=41594862
Are there any good books or other resources yet on realtime programming on Linux?
That article claims that without NO_HZ Linux wouldn’t be running in datacenters. Um, no. Many hyperscalers still haven’t enabled it! Stopped reading there.
The Pi 5 support is surprising, or rather that it's only landing now.
The Raspberry Pi Foundation does not do a good upstream support. It is not very bad, but also not good. They should start adding support for their new chips in the upstream projects before they get into the market, like Intel does it for example. They could add support for some new IP cores, without reveling when and how it will be used later. When the product comes out the only add small patches linking the code together like device tree files.
It would also be good if they would release all the closed source firmware files needed for their devices under a redistributable license in the linux-firmware repository. For some time it was not allowed to redistribute the binary wifi firmware needed for the Raspberry Pi devices. This is needed for Linux distributions to package the binaries.
I hope they do this only because of lack of resources and not intentionally to lock people into their Linux distribution.
As far as I know (source, I still patch the LTS kernels), the fan control of the POE hat for the Pi 4 hasn't been merged yet.
This thing was announced on May 2021...
So not so good is really an understatement.
https://www.raspberrypi.com/news/announcing-the-raspberry-pi...
Its not awful, but its not good either. Pi4 has been a looooong slog, but they also use components that cant be released under GPL license, so there is not much they could upstream for those components
If I went and checked commits, I’m sure there are a lot of business critical IOT/controller type processes that now rely on Raspberry and therefore engineers backing support out the gate
But it's not out of the gate, it's been almost a year.
All relative I guess. “Out the gate” for fairly conservative industrial controllers can probably be measured in months to years.
You never catch them using anything near latest in an application.
Still waiting on SR-IOV for Xe graphics to make it…
Modules are available, but it’s hit-and-miss with updates.
Isn't intel SRIOV getting mainlined with Xe driver in 6.12 or am I mistaken?
It’s a fairly significant feature but it’s not mentioned in the 6.12 pull notes. Various sites mention that it’s “definitely, for sure, this time” mainlined in the next release, but I haven’t seen anything definitive.
I’m just an end user, so I don’t know if it’s been mentioned in a newsgroup somewhere.
So Linux now officially support RTOS capabilities, without patches, which is pretty cool. I wonder, realistically, how many applications that were originally designed to use microcontrollers for real-time purposes, can be migrated to use Linux, which vastly simplifies and lowers the cost development. And having the ability to use high-level languages like Python significantly lowers the barrier to entry. Obviously certain applications require the speed of a MCU without an operating system, but how many projects really don't need dedicated MCUs?
Unfortunately migrating real-time stuff to Linux _doesn't_ necessarily reduce costs or simplify real-time development needs. I've been doing embedded development for 5+ years at a few companies and doing embedded Linux is still a slog. I prefer a good MCU running Nim or other modern language. Heck there's even MicroPython nowadays.
Especially for anything that needs to "just run" for multiple years. Linux means you must deal of the distro or something like Yocto or Buildroot. Both of which have major pain points.
I would think the portability of, say, a Python application running on Linux is a nice benefit. Try switching from one MCU to a totally different one and you may have to start from scratch (e.g. try going from Microchip to STM.) Can you describe why embedded Linux is still a slog? And what do you think it would take for the issues to be addressed?
Doesn't Micropython already get you 95% of the way towards just running the same Python code on multiple MCUs?
Linux is boomer tech. It keeps up with the latest hardware, that’s about it. Even real time is decades old. I would rather hear about the latest crypto Ponzi scheme than the latest Linux release. At least that would be novel.
Ubuntu/Debian/Mint family will get it, one day...
Reminded that Debian-family is outdated linux that uses the marketing 'stable' which has 0 relations to the number of bugs.
Modern Linux like Fedora has those bugs already fixed.
I say this as a warning. I thought we were trapped with Windows 11 and 'Linux'(meaning Debian-family). No, turns out that is outdated linux and Modern linux is amazing.
I'm a bit reluctant to lump Fedora in with 'Linux', because its not fair to Fedora.
Yeah, I have been saying this for years now. Debian and Ubuntu type distros starts doing custom patches and cherry picks changes into 3 year old software, just to keep it chugging along. Sounds like insanity to me. Just upgrade so you are not 3-4 years behind, and by keeping the number of custom patching lower, have a simpler time fixing bugs.