EEVDF regression still exists

[Prundeanu, Cristian]

On 2025-04-29, 16:57, "Peter Zijlstra" <peterz at infradead.org <mailto:peterz at infradead.org>> wrote:

>> Here are the latest results for the EEVDF impact on database workloads.
>> The regression introduced in kernel 6.6 still persists and doesn't look
>> like it is improving.
>
> Well, I was under the impression it had actually been solved :-(
>
> My understanding from the last round was that Prateek and co had it
> sorted -- with the caveat being that you had to stick SCHED_BATCH in at
> the right place in MySQL start scripts or somesuch.

The statement in the previous thread [1] was that using SCHED_BATCH improves 
performance over default. While that still holds true, it is also equally true
about using SCHED_BATCH on kernel 6.5.

So, when we compare 6.5 with recent kernels, both using SCHED_BATCH, the
regression is still visible. (Previously, we only compared SCHED_BATCH with 
6.5 default, leading to the wrong conclusion that it's a fix).

[1] https://lore.kernel.org/all/feb31b6e-6457-454c-a4f3-ce8ad96bf8de@amd.com/