From 7f829bde94b1c97b1804fa5860e066ea49dbfca3 Mon Sep 17 00:00:00 2001 From: Fernand Sieber Date: Wed, 5 Nov 2025 17:25:37 +0200 Subject: [PATCH] sched/core: Optimize core cookie matching check Early return true if the core cookie matches. This avoids the SMT mask loop to check for an idle core, which might be more expensive on wide platforms. Signed-off-by: Fernand Sieber Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: K Prateek Nayak Reviewed-by: Madadi Vineeth Reddy Link: https://patch.msgid.link/20251105152538.470586-1-sieberf@amazon.com --- kernel/sched/sched.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index d04e007608a32..82e74e8ca2eac 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1432,6 +1432,9 @@ static inline bool sched_core_cookie_match(struct rq *rq, struct task_struct *p) if (!sched_core_enabled(rq)) return true; + if (rq->core->core_cookie == p->core_cookie) + return true; + for_each_cpu(cpu, cpu_smt_mask(cpu_of(rq))) { if (!available_idle_cpu(cpu)) { idle_core = false; @@ -1443,7 +1446,7 @@ static inline bool sched_core_cookie_match(struct rq *rq, struct task_struct *p) * A CPU in an idle core is always the best choice for tasks with * cookies. */ - return idle_core || rq->core->core_cookie == p->core_cookie; + return idle_core; } static inline bool sched_group_cookie_match(struct rq *rq, -- 2.47.3