Linux 6.0 Has Some Big Scheduler Changes, Including Improved NUMA Balancing For AMD Zen

[phoronix]

Phoronix: Linux 6.0 Has Some Big Scheduler Changes, Including Improved NUMA Balancing For AMD Zen

Ingo Molnar today submitted the main set of kernel scheduler updates for the in-development Linux 6.0 (nee 5.20). The scheduler updates contain some notable changes that will be interesting to benchmark in the days ahead...

https://www.phoronix.com/news/Linux-6.0-Scheduler

[Mahboi]

Thus, we shall 5.20 blaze it to 6.0.

[waxhead]

Now this is the kind of news I like... not that I think that I will benefit much from it myself , but I find this interesting as hell.

I actually wrote a C program that offline/online cores by writing o or 1 to "/sys/devices/system/cpu/cpuN/online depending on the CPU load (picked from /proc/stat) just to see how my system performed with "less CPU's". The idea being to simply max out one CPU before enabling other CPU's instead of spreading the work over all the CPU's available.

To my surprise, the user experience (did not do any meaningful benchmarks) was not even noticeable once I tuned my program to keep a spare CPU online to handle intermittent peak loads in addition to the CPU's fully occupied.

Unless I am mistaken / things have changed a lot, Hardware that allow hot swapping CPU's will turn them completely off (no power) . I wonder how much energy would be saved if mostly idle cores are completely turned off instead of idling at a low power state, especially on large core servers. Would it even be noticeable?

[Vorpal]

Typo: "Another notable scheduler chnage for Linux 6.0"