More RT Code Out For Review, RT Patches Updated Against Linux 5.14

[phoronix]

Phoronix: More RT Code Out For Review, RT Patches Updated Against Linux 5.14

The real-time (RT) patches for the Linux kernel still appear a ways off from mainline but at least there is movement on this important patch series for embedded and other use-cases needing real-time support...

https://www.phoronix.com/scan.php?page=news_item&px=Linux-5.14-RT-Updates

[tildearrow]

Typos:

and some AR64 fixes also incorporated.

Also on Friday a set of 63 patches around the PREEMPT-RT locking infrastructure was posted for review. This represents most of RT's locking code These patches shouldn't affect non-RT

(should be ARM64; and missing period)

[uid313]

When can we hope to see the RT patches mainlined?

Do all of the RT patches need to be mainlined at the same time as one big merge? Or would it be possible to merge some patches for one release, then later merge more patches?

[wertigon]

When can we hope to see the RT patches mainlined?

Do all of the RT patches need to be mainlined at the same time as one big merge? Or would it be possible to merge some patches for one release, then later merge more patches?

All of it? 2022 at the earliest. However, most of it is already mainlined, compared to a couple years ago. Compare the patchset between 4.4 and 5.12, for instance - a reduction of around 200 patches.

https://wiki.linuxfoundation.org/rea...pt_rt_versions

You are correct a lot of it will be brought in to mainline in chunks. The biggest chunks will probably go in now, that is SoftIRQ, RTMutex and printk modifications. After that the changes will be iteratively smaller, and work will be a lot easier I'd say.

[DL9220]

Hmmm, Xanmod is doing a RT-kernel.... I'm happy with his CaCule but I guess some of you would like to give it a spin.

https://xanmod.org/

Cheers

[perpetually high]

I just added support for this to my Ubuntu build script if anyone wants to compile 5.14-rc3 rt kernel for themselves on their machines.

EDIT: I made some updates to the script. And added a commit with some instructions on how to get 5.4 LTS, 5.10 LTS, and 5.13 mainline going in different flavors. I'll get a readme going soon but I don't want to waste time editing a readme constantly. But at least this commit message has enough to get going


----

Steps:

1) git clone <this repo>
2) cd build-ubuntu-kernel
3) ./build_kernel.sh

I ran the above and can verify it builds and compiles and I booted into and typing from it now:

$ uname -a
Linux ubuntu 5.14-rc3-051400rc3+customrt-generic #051400rc3+202107311230 SMP PREEMPT_RT Sat Jul 31 08:38:44 PDT 2 x86_64 x86_64 x86_64 GNU/Linux

I wouldn't recommend an -rt or -rc3 (double whammy) for a daily driver, but probably a good way to test both the new RT patches and 5.14-rc3.

AMD users can also pass in AMDGPU_BUILTIN=yes in the beginning for smoother bootup and such. I added support for Polaris, Vega, Navi, Raven, and Renoir out the box. The overhead from the extra blobs should be nonexistant.