[FR] Select CPUs/Cores klipper runs on

Features
1

Not sure if this is a hardware issue, linux issue or klipper issue, but I’m running an OrangePi 5 which has an RK3588s SOC which has 4 A76 cores and 4 A55 cores in a big.LITTLE configuration. I was getting some wonky performance. QGL /bed mesh in particular had many noticeable pauses, occasional timeouts. At first I was blaming my CAN setup (which probably was exacerbating the situation), but on a whim I disabled all of the little cores and now everything runs beautifully.

My thought was if klipper itself can limit itself to run only on certain cores (defined in a config file perhaps), that could help solve some timing issues that might arise from heterogenous processors.

2

It could also be OS related.

I’m running Armbian on a Odroid X4U (32 bit) with no issues in QGL or ABL.

**Host** (armv7l, 32bit)
Version: v0.11.0-52-g40d8c2ef
OS: Debian GNU/Linux 10 (buster)
Distro: armbian

Armbian builds are specific per SBC, so there could be some OrangePi/Odroid build differences that might make Klipper operate differently. .

3

You can try to Set the cpu affinity in the systemd klipper Service file like this:

[Service]
CPUAffinity=13

You have to calculate the Correct Mask for your cores you want to run klipper on

After that:

Sudo systemctl daemon-reload

After that

Sudo service klipper restart

5

Late reply, but thanks for the tips. That worked perfectly.

For reference you don’t need to calculate the mask (though it’s not hard if you know binary). The below for example limits things to core 6 and 7

CPUAffinity=6 7
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