sched/fair: More complex proportional newidle balance

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It turns out that a few workloads (easyWave, fio) have a fairly low
success rate on newidle balance, but still benefit greatly from having
it anyway.

Luckliky these workloads have a faily low newidle rate, so the cost if
doing the newidle is relatively low, even if unsuccessfull.

Add a simple rate based part to the newidle ratio compute, such that
low rate newidle will still have a high newidle ratio.

This cures the easyWave and fio workloads while not affecting the
schbench numbers either (which have a very high newidle rate).

Reported-by: Mario Roy <marioeroy@gmail.com>
Reported-by: "Mohamed Abuelfotoh, Hazem" <abuehaze@amazon.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Mario Roy <marioeroy@gmail.com>
Tested-by: "Mohamed Abuelfotoh, Hazem" <abuehaze@amazon.com>
Link: https://patch.msgid.link/20260127151748.GA1079264@noisy.programming.kicks-ass.net

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This commit is contained in:

Peter Zijlstra 2026-01-27 16:17:48 +01:00

parent 3b68df9781

commit 9fe89f022c

4 changed files with 30 additions and 2 deletions

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1

include/linux/sched/topology.h

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27

kernel/sched/fair.c

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1

kernel/sched/features.h

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3

kernel/sched/topology.c

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