[PATCH 0/4] sched/fair: Core sched wake up path improvements

Fernand Sieber
2025-09-22T12:40:10Z

This patch series addresses several issues and improvements in the core
scheduling within the fair scheduler's wake-up paths. The overall result
is better task placement reducing force idle.

The main issues addressed are as follows:

Slow path:
1. Fix incorrect cookie matching logic that wrongly discards idle cores
2. Better fallback logic when no cookie matching target is found

Fast path:
3. Add cookie checks in wake affine idle to prevent force idle
4. Enhance task selection in select idle sibling to consider cookies

Fernand Sieber (4):
sched/fair: Fix cookie check on __select_idle_cpu()
sched/fair: Still look for the idlest cpu with no matching cookie
sched/fair: Add cookie checks on wake idle path
sched/fair: Add more core cookie check in wake up fast path

kernel/sched/fair.c | 49 ++++++++++++++++++++++++++++++++------------
kernel/sched/sched.h | 41 ++++++++++++++++++++----------------
2 files changed, 59 insertions(+), 31 deletions(-)

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2.43.0