❯ uname -a
Linux cachyos-x8664 6.11.4-rt7-1-cachyos-gcc-lazy #1 SMP PREEMPT_DYNAMIC Mon, 21 Oct 2024 20:47:32 +0000 x86_64 GNU/Linux
Check it out at CachyMod.
Some insights into PREEMPT_LAZY at The long road to lazy preemption
I’ve tried out PREEMPT_LAZY and generally it sucks at responsiveness under load. I may revisit it in 6.12 but if the results are the same as 6.11, we won’t consider it.
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I’ve tried it out again in 6.12. It performs well and may even be a contender for the default option in our default kernel. I had a bad experience with it in 6.11 due to me not cherrypicking all the patches necessary, i.e. I’ve only grabbed patches from [PATCH 0/7] Lazy preemption bits and not clearmod/patches/sched_eevdf_allow_shorter_slices_to_wakeup-preempt.patch at main · marioroy/clearmod · GitHub which is needed for EEVDF to actually preempt tasks.
In case there are misunderstandings, the CachyMod project is great at enabling users to use PREEMPT_LAZY on 6.11 kernel. The 2nd patch I mentioned above is already upstreamed in 6.12 and I had a great experience with lazy here, which was not the case when I tried out PREEMPT_LAZY in 6.11 for myself.
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