Messages in this thread Patch in this message | ![/](/images/icornerl.gif) | | From | Kyle Meyer <> | Subject | [PATCH 2/2 RESEND] sched/topology: Optimize topology_span_sane() | Date | Tue, 9 Apr 2024 10:52:50 -0500 |
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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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