diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2023-09-17 11:10:23 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2023-09-17 11:10:23 -0700 |
commit | e5a710d13247975444c9a18e28413e566c334271 (patch) | |
tree | 6d03a36d7cd3d04902c80d387726d28f4e4846f6 | |
parent | e54ca3c81f2d81e4de3339873256e568f60ce076 (diff) | |
parent | 108af4b4bd3813610701379a58538e3339b162e4 (diff) |
Merge tag 'sched-urgent-2023-09-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Ingo Molnar:
"Fix a performance regression on large SMT systems, an Intel SMT4
balancing bug, and a topology setup bug on (Intel) hybrid processors"
* tag 'sched-urgent-2023-09-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/sched: Restore the SD_ASYM_PACKING flag in the DIE domain
sched/fair: Fix SMT4 group_smt_balance handling
sched/fair: Optimize should_we_balance() for large SMT systems
-rw-r--r-- | arch/x86/kernel/smpboot.c | 12 | ||||
-rw-r--r-- | kernel/sched/fair.c | 27 |
2 files changed, 34 insertions, 5 deletions
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 4e45ff44aa07..48e040618731 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -579,7 +579,6 @@ static bool match_llc(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o) } -#if defined(CONFIG_SCHED_SMT) || defined(CONFIG_SCHED_CLUSTER) || defined(CONFIG_SCHED_MC) static inline int x86_sched_itmt_flags(void) { return sysctl_sched_itmt_enabled ? SD_ASYM_PACKING : 0; @@ -603,7 +602,14 @@ static int x86_cluster_flags(void) return cpu_cluster_flags() | x86_sched_itmt_flags(); } #endif -#endif + +static int x86_die_flags(void) +{ + if (cpu_feature_enabled(X86_FEATURE_HYBRID_CPU)) + return x86_sched_itmt_flags(); + + return 0; +} /* * Set if a package/die has multiple NUMA nodes inside. @@ -640,7 +646,7 @@ static void __init build_sched_topology(void) */ if (!x86_has_numa_in_package) { x86_topology[i++] = (struct sched_domain_topology_level){ - cpu_cpu_mask, SD_INIT_NAME(DIE) + cpu_cpu_mask, x86_die_flags, SD_INIT_NAME(DIE) }; } diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 8dbff6e7ad4f..cb225921bbca 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6619,6 +6619,7 @@ dequeue_throttle: /* Working cpumask for: load_balance, load_balance_newidle. */ static DEFINE_PER_CPU(cpumask_var_t, load_balance_mask); static DEFINE_PER_CPU(cpumask_var_t, select_rq_mask); +static DEFINE_PER_CPU(cpumask_var_t, should_we_balance_tmpmask); #ifdef CONFIG_NO_HZ_COMMON @@ -9579,7 +9580,7 @@ static inline long sibling_imbalance(struct lb_env *env, imbalance /= ncores_local + ncores_busiest; /* Take advantage of resource in an empty sched group */ - if (imbalance == 0 && local->sum_nr_running == 0 && + if (imbalance <= 1 && local->sum_nr_running == 0 && busiest->sum_nr_running > 1) imbalance = 2; @@ -9767,6 +9768,15 @@ static bool update_sd_pick_busiest(struct lb_env *env, break; case group_smt_balance: + /* + * Check if we have spare CPUs on either SMT group to + * choose has spare or fully busy handling. + */ + if (sgs->idle_cpus != 0 || busiest->idle_cpus != 0) + goto has_spare; + + fallthrough; + case group_fully_busy: /* * Select the fully busy group with highest avg_load. In @@ -9806,6 +9816,7 @@ static bool update_sd_pick_busiest(struct lb_env *env, else return true; } +has_spare: /* * Select not overloaded group with lowest number of idle cpus @@ -10917,6 +10928,7 @@ static int active_load_balance_cpu_stop(void *data); static int should_we_balance(struct lb_env *env) { + struct cpumask *swb_cpus = this_cpu_cpumask_var_ptr(should_we_balance_tmpmask); struct sched_group *sg = env->sd->groups; int cpu, idle_smt = -1; @@ -10940,8 +10952,9 @@ static int should_we_balance(struct lb_env *env) return 1; } + cpumask_copy(swb_cpus, group_balance_mask(sg)); /* Try to find first idle CPU */ - for_each_cpu_and(cpu, group_balance_mask(sg), env->cpus) { + for_each_cpu_and(cpu, swb_cpus, env->cpus) { if (!idle_cpu(cpu)) continue; @@ -10953,6 +10966,14 @@ static int should_we_balance(struct lb_env *env) if (!(env->sd->flags & SD_SHARE_CPUCAPACITY) && !is_core_idle(cpu)) { if (idle_smt == -1) idle_smt = cpu; + /* + * If the core is not idle, and first SMT sibling which is + * idle has been found, then its not needed to check other + * SMT siblings for idleness: + */ +#ifdef CONFIG_SCHED_SMT + cpumask_andnot(swb_cpus, swb_cpus, cpu_smt_mask(cpu)); +#endif continue; } @@ -12918,6 +12939,8 @@ __init void init_sched_fair_class(void) for_each_possible_cpu(i) { zalloc_cpumask_var_node(&per_cpu(load_balance_mask, i), GFP_KERNEL, cpu_to_node(i)); zalloc_cpumask_var_node(&per_cpu(select_rq_mask, i), GFP_KERNEL, cpu_to_node(i)); + zalloc_cpumask_var_node(&per_cpu(should_we_balance_tmpmask, i), + GFP_KERNEL, cpu_to_node(i)); #ifdef CONFIG_CFS_BANDWIDTH INIT_CSD(&cpu_rq(i)->cfsb_csd, __cfsb_csd_unthrottle, cpu_rq(i)); |