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

Mohamed Abuelfotoh, Hazem abuehaze at amazon.com
Fri Oct 18 02:54:19 PDT 2024


>> 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



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