High max jitter

Hello there,

actually i am having a high max jitter, i tried to run linuxcnc on my raspberry pi 4 and when i run the latency test i got values of servo thread of about 88972574 and base of 50056722 like in this image drive.google.com/file/d/1Dx10cUhac0YA6R9...sK/view?usp=drivesdk, and i don't know how to solve it, is it possible?

i tired with another build and the this was the values drive.google.com/file/d/1EH_aMwVQL3exWtA...7a/view?usp=drivesdk

thanks, and sorry if i miss something

It looks like you are not using a real time kernel.

What does the command

uname a

report?
 

when i use the command it report this

Linux rpi 6.1.0-rpi6-rpi-v8 #1 SMP PREEMPT Debian 1:6.1.58-1+rpt2 (2023-10-27) a

OK, that's a real time kernel so the problem is elsewhere

Is force_turbo enabled in your config.txt file?

It may also be that a 25KHz base thread is too fast for the RPI
so running the base thread at a lower speed during the test
may improve the results.

latency-test --help

for how to do this

force_turbo isnt enable, but arm_boost is enable,

is that?

I think you have to enable force_turbo or the RPI will change CPU clock speeds
while running, causing massive delays because the CPU is halted until the PLL
reaches the new frequency.

I would probably not use arm_boost until you have some CPU temperature data