Steven Barrett commented on issue #104 at Alfred Chen / linux-prjc

Steven Barrett
2025-07-03T18:16:32Z

@alfredchen ok, I think I figured out what's going on here, I've been booting my system with nosmt in the kernel boot parameters. If I remove this boot parameter, nice bench returns output like it should.

However, if I boot with nosmt or use smt-manager (https://github.com/damentz/smt-manager), to turn off logical cores after boot, PDS appears to not understand how to schedule with respect to nice levels.

Last interesting point, if I disable SMT in the BIOS, your scheduler works as intended when running the benchmark.

This makes me think that there's an issue with PDS's ability to schedule when one or more boot time CPU cores or threads are offlined after boot for any reason, including nosmt as a kernel boot time parameter. Maybe there needs to be some type of offline or online hook that runs to rebalance some data structure whenever the CPU topology changes?