diff options
| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2010-04-16 14:59:29 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2010-04-23 11:02:02 +0200 |
| commit | 669c55e9f99b90e46eaa0f98a67ec53d46dc969a (patch) | |
| tree | 9f60bcf779e5ec786c05b8053b59e091edcb418c /kernel/sched_fair.c | |
| parent | sched: Cure load average vs NO_HZ woes (diff) | |
| download | linux-669c55e9f99b90e46eaa0f98a67ec53d46dc969a.tar.xz linux-669c55e9f99b90e46eaa0f98a67ec53d46dc969a.zip | |
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_fair.c')
| -rw-r--r-- | kernel/sched_fair.c | 12 |
1 files changed, 5 insertions, 7 deletions
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 88d3053ac7c2..0a413c7e3ab8 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -1508,9 +1508,7 @@ select_task_rq_fair(struct rq *rq, struct task_struct *p, int sd_flag, int wake_ * Pick the largest domain to update shares over */ tmp = sd; - if (affine_sd && (!tmp || - cpumask_weight(sched_domain_span(affine_sd)) > - cpumask_weight(sched_domain_span(sd)))) + if (affine_sd && (!tmp || affine_sd->span_weight > sd->span_weight)) tmp = affine_sd; if (tmp) { @@ -1554,10 +1552,10 @@ select_task_rq_fair(struct rq *rq, struct task_struct *p, int sd_flag, int wake_ /* Now try balancing at a lower domain level of new_cpu */ cpu = new_cpu; - weight = cpumask_weight(sched_domain_span(sd)); + weight = sd->span_weight; sd = NULL; for_each_domain(cpu, tmp) { - if (weight <= cpumask_weight(sched_domain_span(tmp))) + if (weight <= tmp->span_weight) break; if (tmp->flags & sd_flag) sd = tmp; @@ -2243,7 +2241,7 @@ unsigned long __weak arch_scale_freq_power(struct sched_domain *sd, int cpu) unsigned long default_scale_smt_power(struct sched_domain *sd, int cpu) { - unsigned long weight = cpumask_weight(sched_domain_span(sd)); + unsigned long weight = sd->span_weight; unsigned long smt_gain = sd->smt_gain; smt_gain /= weight; @@ -2276,7 +2274,7 @@ unsigned long scale_rt_power(int cpu) static void update_cpu_power(struct sched_domain *sd, int cpu) { - unsigned long weight = cpumask_weight(sched_domain_span(sd)); + unsigned long weight = sd->span_weight; unsigned long power = SCHED_LOAD_SCALE; struct sched_group *sdg = sd->groups; |