sched/fair: Drop idle recency from slow-path CPU selection

The slow-path CPU picker favours the most recently idle CPU as a proxy
for cache warmth.

A more recent idle stamp may make ongoing entry more likely. If entry
cannot be aborted, that CPU must finish entry and then exit, potentially
paying more than an already-resident CPU with the same advertised exit
latency. The advertised worst-case latency covers both cases. idle_stamp
does not timestamp the current CPUIdle entry, so this is only a heuristic.

A recent scheduler-idle transition may also mark a short gap in recurring
task activity, making the CPU likely to be busy again soon.

Drop the timestamp tie-break and retain the first candidate unless a
lower advertised exit latency is found.

Signed-off-by: Christian Loehle <christian.loehle@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://patch.msgid.link/20260917153915.1563875-2-christian.loehle@arm.com

0 files changed, 0 insertions, 0 deletions