Re: [PATCH 0/2] [tip: sched/core] sched: Disable PLACE_LAG and RUN_TO_PARITY and move them to sysctl

From: Mohamed Abuelfotoh, Hazem
Date: Fri Oct 18 2024 - 05:54:44 EST


And sysctl is arguably more of an ABI than debugfs, which
doesn't really sound suitable for workaround.

And I don't see how adding a line to /etc/rc.local is harder than adding
a line to /etc/sysctl.conf

Adding a line is equally difficult both ways, you're right. But aren't
most distros better equipped to manage (persist, modify, automate) sysctl
parameters in a standardized manner?
Whereas rc.local seems more "individual need / edge case" oriented. For
instance: changes are done by editing the file, which is poorly scriptable
(unlike the sysctl command, which is a unified interface that reconciles
changes); the load order is also typically late in the boot stage, making
it not an ideal place for settings that affect system processes.


I'd add to what Cristian mentioned is that having these tunables as sysctls will make them more detectable to the end users because checking output of sysctl -a is usually one of the first steps during performance troubleshooting vs checking /sys/kernel/debug/sched/ files so it's easier for people to spot these configurations as sysctls if they notice performance difference after upgrading the kernel.

Hazem