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| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2010-04-16 12:59:29 (GMT) |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2010-04-23 09:02:02 (GMT) |
| commit | 669c55e9f99b90e46eaa0f98a67ec53d46dc969a (patch) | |
| tree | 9f60bcf779e5ec786c05b8053b59e091edcb418c /kernel/sched.c | |
| parent | 74f5187ac873042f502227701ed1727e7c5fbfa9 (diff) | |
| download | linux-669c55e9f99b90e46eaa0f98a67ec53d46dc969a.tar.xz | |
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 <davem@davemloft.net>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/sched.c')
| -rw-r--r-- | kernel/sched.c | 3 |
1 files changed, 3 insertions, 0 deletions
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; |