From 669c55e9f99b90e46eaa0f98a67ec53d46dc969a Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 16 Apr 2010 14:59:29 +0200 Subject: sched: Pre-compute cpumask_weight(sched_domain_span(sd)) Dave reported that his large SPARC machines spend lots of time in hweight64(), try and optimize some of those needless cpumask_weight() invocations (esp. with the large offstack cpumasks these are very expensive indeed). Reported-by: David Miller Signed-off-by: Peter Zijlstra LKML-Reference: Signed-off-by: Ingo Molnar --- kernel/sched.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'kernel/sched.c') diff --git a/kernel/sched.c b/kernel/sched.c index 0cc913a..4956ed0 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -6271,6 +6271,9 @@ cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu) struct rq *rq = cpu_rq(cpu); struct sched_domain *tmp; + for (tmp = sd; tmp; tmp = tmp->parent) + tmp->span_weight = cpumask_weight(sched_domain_span(tmp)); + /* Remove the sched domains which do not contribute to scheduling. */ for (tmp = sd; tmp; ) { struct sched_domain *parent = tmp->parent; -- cgit v1.1