diff options
| author | Dmitry Torokhov <[email protected]> | 2022-10-09 22:30:23 -0700 |
|---|---|---|
| committer | Dmitry Torokhov <[email protected]> | 2022-10-09 22:30:23 -0700 |
| commit | 5f8f8574c7f5585b09a9623f0f13462e4eb67b4d (patch) | |
| tree | 8f1d5e88bf9604a9e39fbcce0e37b3d8cee451bb /kernel/sched/topology.c | |
| parent | e62563db857f81d75c5726a35bc0180bed6d1540 (diff) | |
| parent | fe5b6aaef72a0f7daa06e7960e0bee45c2984e41 (diff) | |
Merge branch 'next' into for-linus
Prepare input updates for 6.1 merge window.
Diffstat (limited to 'kernel/sched/topology.c')
| -rw-r--r-- | kernel/sched/topology.c | 23 |
1 files changed, 15 insertions, 8 deletions
diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c index 05b6c2ad90b9..8739c2a5a54e 100644 --- a/kernel/sched/topology.c +++ b/kernel/sched/topology.c @@ -2316,23 +2316,30 @@ build_sched_domains(const struct cpumask *cpu_map, struct sched_domain_attr *att /* * For a single LLC per node, allow an - * imbalance up to 25% of the node. This is an - * arbitrary cutoff based on SMT-2 to balance - * between memory bandwidth and avoiding - * premature sharing of HT resources and SMT-4 - * or SMT-8 *may* benefit from a different - * cutoff. + * imbalance up to 12.5% of the node. This is + * arbitrary cutoff based two factors -- SMT and + * memory channels. For SMT-2, the intent is to + * avoid premature sharing of HT resources but + * SMT-4 or SMT-8 *may* benefit from a different + * cutoff. For memory channels, this is a very + * rough estimate of how many channels may be + * active and is based on recent CPUs with + * many cores. * * For multiple LLCs, allow an imbalance * until multiple tasks would share an LLC * on one node while LLCs on another node - * remain idle. + * remain idle. This assumes that there are + * enough logical CPUs per LLC to avoid SMT + * factors and that there is a correlation + * between LLCs and memory channels. */ nr_llcs = sd->span_weight / child->span_weight; if (nr_llcs == 1) - imb = sd->span_weight >> 2; + imb = sd->span_weight >> 3; else imb = nr_llcs; + imb = max(1U, imb); sd->imb_numa_nr = imb; /* Set span based on the first NUMA domain. */ |