feecat / rpi-rt

raspberry os preempt rt compiled patch

rpi-rt

raspberry os preempt rt compiled patch

---

I have noticed 4.19.y-rt of raspberry/linux has not been updated for a long time, and no one has reviewed the submission. It seems that Tiejun Chen has no time and no one can replace this task.
lemariva/RT-Tools-RPi is very useful, but only updated to 4.19.59_rt23. In raspberry/linux its 4.19.71_rt24

I found that SR4ven did an rt patch on a fork. I downloaded it and compiled it, and it worked fine.Its 4.19.127_rt55.
For the convenience, I will publish it as a separate package. But please don't forget to thank SR4ven.
In addition, I found this post on the linuxcnc forum that provides a 64-bit preempt-rt patched kernel 5.4.61_rt37 package.
Great Thanks for these guy.

For download please visit release page

For how-to-use please visit lemariva's tutorial at Installing the Kernel Image, Modules & Device Tree Overlays.

NOTE: For now this two package only support rpi4(bcm2711).

---

real-time test tool

The code for testing real-time performance from Realtime Linux and mklatencyplot.bash.
I did not successfully install png support, So I changed it to export SVG and simply tested it. Sources code see here.
The following is the test situation with 4.19.127_rt55:

IDLE:

Mid Use:

CPU0 Full Use:

---

Useful links

raspberrypi/linux#3172
raspberrypi/linux#3736