Recently I am trying to use a multi-GPU render farm for Karma. However that machine is for GPU render, which is not supposed to let CPU run full speed all time. So I am thinking of is there a place that I can only let GPU render at XPU mode?
I guess probably the SideFX developed Karma XPU in a way that cpu and gpu are deeply working together? Or has anyone meet the similar issue?
Thank you!

Here is a way, its all in the environment variables
https://www.sidefx.com/forum/topic/87885/?page=1#post-379392 [www.sidefx.com]

From the docs here: https://www.sidefx.com/docs/houdini/solaris/karma_xpu.html [www.sidefx.com]

KARMA_XPU_DISABLE_EMBREE_DEVICE
If this env var is set, Karma XPU will not use any Embree CPU devices.

So it sounds like you can set this variable to 1 in your houdini.env or system environment and it should no longer bother with the CPU.

-Edit: AslakKS beat me to it

That works! Thank you AslakKS and Siavash!