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 --- include/linux/sched.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'include/linux/sched.h') diff --git a/include/linux/sched.h b/include/linux/sched.h index ea1b5f32ec5c..c551e6a1447e 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -604,6 +604,11 @@ extern int groups_search(struct group_info *group_info, gid_t grp); #define GROUP_AT(gi, i) \ ((gi)->blocks[(i)/NGROUPS_PER_BLOCK][(i)%NGROUPS_PER_BLOCK]) +#ifdef ARCH_HAS_PREFETCH_SWITCH_STACK +extern void prefetch_stack(struct task_struct*); +#else +static inline void prefetch_stack(struct task_struct *t) { } +#endif struct audit_context; /* See audit.c */ struct mempolicy; -- cgit v1.2.3