From 383f2835eb9afb723af71850037b2f074ac9db60 Mon Sep 17 00:00:00 2001 From: "Chen, Kenneth W" Date: Fri, 9 Sep 2005 13:02:02 -0700 Subject: [PATCH] Prefetch kernel stacks to speed up context switch For architecture like ia64, the switch stack structure is fairly large (currently 528 bytes). For context switch intensive application, we found that significant amount of cache misses occurs in switch_to() function. The following patch adds a hook in the schedule() function to prefetch switch stack structure as soon as 'next' task is determined. This allows maximum overlap in prefetch cache lines for that structure. Signed-off-by: Ken Chen Cc: Ingo Molnar Cc: "Luck, Tony" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/sched.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 18b95520a2e2..2632b812cf24 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2888,6 +2888,7 @@ switch_tasks: if (next == rq->idle) schedstat_inc(rq, sched_goidle); prefetch(next); + prefetch_stack(next); clear_tsk_need_resched(prev); rcu_qsctr_inc(task_cpu(prev)); -- cgit v1.2.3