Messages in this thread | ![/](/images/icornerl.gif) | | Date | Wed, 20 Mar 2024 11:32:05 -0700 | From | Yury Norov <> | Subject | Re: [PATCH 2/2] sched/topology: Optimize topology_span_sane() |
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On Tue, Mar 19, 2024 at 01:51:48PM -0500, Kyle Meyer wrote: > Optimize topology_span_sane() by removing duplicate comparisons. > > The total number of comparisons is reduced from N * (N - 1) to > N * (N - 1) / 2 (per non-NUMA scheduling domain level). > > Signed-off-by: Kyle Meyer <kyle.meyer@hpe.com>
Reviewed-by: Yury Norov <yury.norov@gmail.com>
> --- > kernel/sched/topology.c | 6 ++---- > 1 file changed, 2 insertions(+), 4 deletions(-) > > diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c > index 99ea5986038c..b6bcafc09969 100644 > --- a/kernel/sched/topology.c > +++ b/kernel/sched/topology.c > @@ -2347,7 +2347,7 @@ static struct sched_domain *build_sched_domain(struct sched_domain_topology_leve > static bool topology_span_sane(struct sched_domain_topology_level *tl, > const struct cpumask *cpu_map, int cpu) > { > - int i; > + int i = cpu + 1; > > /* NUMA levels are allowed to overlap */ > if (tl->flags & SDTL_OVERLAP) > @@ -2359,9 +2359,7 @@ static bool topology_span_sane(struct sched_domain_topology_level *tl, > * breaking the sched_group lists - i.e. a later get_group() pass > * breaks the linking done for an earlier span. > */ > - for_each_cpu(i, cpu_map) { > - if (i == cpu) > - continue; > + for_each_cpu_from(i, cpu_map) { > /* > * We should 'and' all those masks with 'cpu_map' to exactly > * match the topology we're about to build, but that can only > -- > 2.44.0
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