Re: [PATCH 0/4] sched: Various reweight_entity() fixes
From: Peter Zijlstra
Date: Wed Feb 11 2026 - 05:53:04 EST
On Wed, Feb 11, 2026 at 10:01:44AM +0100, Peter Zijlstra wrote:
> > There 2 issues with patch 3
> >
> > *one scale_load_down remains in avg_vruntime
> >
> > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> > index 25c398ff0d59..3143ae7f07b0 100644
> > --- a/kernel/sched/fair.c
> > +++ b/kernel/sched/fair.c
> > @@ -778,7 +778,7 @@ u64 avg_vruntime(struct cfs_rq *cfs_rq)
> >
> > if (weight) {
> > if (curr) {
> > - unsigned long w = scale_load_down(curr->load.weight);
> > + unsigned long w =
> > avg_vruntime_weight(curr->load.weight);
> >
> > runtime += entity_key(cfs_rq, curr) * w;
> > weight += w;
>
> AAARGHHH!! Sorry about that, clearly I've not been careful with
> reshuffling patches :-(
So with that one fixed; I get (as queue/sched/core of just now):
base:
1: 0.25431 +- 0.00226 seconds time elapsed ( +- 0.89% )
2: 0.52522 +- 0.00304 seconds time elapsed ( +- 0.58% )
5: 1.10452 +- 0.00509 seconds time elapsed ( +- 0.46% )
10: 2.00673 +- 0.00761 seconds time elapsed ( +- 0.38% )
20: 3.81795 +- 0.00347 seconds time elapsed ( +- 0.09% )
40: 7.0551 +- 0.0112 seconds time elapsed ( +- 0.16% )
+1 patches/peterz-sched-fair-fix-zero_vruntime.patch
1: 0.25231 +- 0.00328 seconds time elapsed ( +- 1.30% )
2: 0.52794 +- 0.00337 seconds time elapsed ( +- 0.64% )
5: 1.09336 +- 0.00391 seconds time elapsed ( +- 0.36% )
10: 1.98787 +- 0.00660 seconds time elapsed ( +- 0.33% )
20: 3.75865 +- 0.00782 seconds time elapsed ( +- 0.21% )
40: 7.0208 +- 0.0102 seconds time elapsed ( +- 0.15% )
+2 patches/peterz-sched-fair-curb-set_protect_slice.patch
1: 0.25421 +- 0.00351 seconds time elapsed ( +- 1.38% )
2: 0.53178 +- 0.00308 seconds time elapsed ( +- 0.58% )
5: 1.09421 +- 0.00462 seconds time elapsed ( +- 0.42% )
10: 1.99843 +- 0.00289 seconds time elapsed ( +- 0.14% )
20: 3.77249 +- 0.00676 seconds time elapsed ( +- 0.18% )
40: 7.0371 +- 0.0143 seconds time elapsed ( +- 0.20% )
+3 patches/wang_tao-sched_eevdf-update_se-_vprot_in_reweight_entity.patch
1: 0.25141 +- 0.00342 seconds time elapsed ( +- 1.36% )
2: 0.53294 +- 0.00474 seconds time elapsed ( +- 0.89% )
5: 1.10944 +- 0.00447 seconds time elapsed ( +- 0.40% )
10: 2.00012 +- 0.00366 seconds time elapsed ( +- 0.18% )
20: 3.77650 +- 0.00796 seconds time elapsed ( +- 0.21% )
40: 7.0455 +- 0.0145 seconds time elapsed ( +- 0.21% )
+4 patches/peter_zijlstra-sched_fair-increase_max_lag_clamping.patch
1: 0.25096 +- 0.00415 seconds time elapsed ( +- 1.65% )
2: 0.53635 +- 0.00372 seconds time elapsed ( +- 0.69% )
5: 1.12040 +- 0.00549 seconds time elapsed ( +- 0.49% )
10: 2.00447 +- 0.00518 seconds time elapsed ( +- 0.26% )
20: 3.7682 +- 0.0104 seconds time elapsed ( +- 0.28% )
40: 7.0023 +- 0.0141 seconds time elapsed ( +- 0.20% )
+5 patches/peterz-sched-increase-avg-bits.patch
1: 0.24866 +- 0.00284 seconds time elapsed ( +- 1.14% )
2: 0.52756 +- 0.00310 seconds time elapsed ( +- 0.59% )
5: 1.09946 +- 0.00643 seconds time elapsed ( +- 0.58% )
10: 1.98256 +- 0.00398 seconds time elapsed ( +- 0.20% )
20: 3.75988 +- 0.00611 seconds time elapsed ( +- 0.16% )
40: 6.9833 +- 0.0113 seconds time elapsed ( +- 0.16% )
+6 patches/peterz-sched-revert-reweight-entity-thingy.patch
1: 0.25302 +- 0.00285 seconds time elapsed ( +- 1.13% )
2: 0.53040 +- 0.00383 seconds time elapsed ( +- 0.72% )
5: 1.08806 +- 0.00341 seconds time elapsed ( +- 0.31% )
10: 1.97696 +- 0.00592 seconds time elapsed ( +- 0.30% )
20: 3.75393 +- 0.00622 seconds time elapsed ( +- 0.17% )
40: 6.9794 +- 0.0139 seconds time elapsed ( +- 0.20% )
Now let me go check on that latency thing from Doug (although hopefully
that was the same boo-boo).