Re: Can we backport EEVDF performance fixes to 6.6?

[Thomas Winter]

On Thu, 2025-07-17 at 16:18 +1200, Thomas Winter wrote:
> Hi All,
> 
> After upgrading a product from 5.15 to 6.6, we found that performance
> took a hit on some workloads. Narrowed this down to the switch to
> EEVDF.
> 
> I backported commit 6d71a9c61604 "sched/fair: Fix EEVDF entity
> placement bug causing scheduling lag" which appears to mostly resolve
> the issue.
> 
> I also applied related commits 4423af84b297 "sched/fair: optimize the
> PLACE_LAG when se->vlag is zero" and c70fc32f4443 "sched/fair: Adhere
> to place_entity() constraints" to avoid the warnings referenced
> there.
> 
> Can these patches be safely backported to 6.6? We would prefer to use
> an official 6.6 release with the fixes.
> Otherwise we have to wait for the next LTS to get these changes which
> were put in 6.13.
> 
> Regards,
> Thomas Winter

Sorry for resending, but my email decided not to send to Ingo or Peter.