Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751537AbcJALqI (ORCPT ); Sat, 1 Oct 2016 07:46:08 -0400 Received: from mga03.intel.com ([134.134.136.65]:15462 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751136AbcJALqC (ORCPT ); Sat, 1 Oct 2016 07:46:02 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.31,426,1473145200"; d="scan'208";a="1059147129" From: Srinivas Pandruvada To: rjw@rjwysocki.net, tglx@linutronix.de, mingo@redhat.com, bp@suse.de Cc: x86@kernel.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, peterz@infradead.org, tim.c.chen@linux.intel.com, jolsa@redhat.com, Srinivas Pandruvada Subject: [PATCH v5 1/9] sched: Extend scheduler's asym packing Date: Sat, 1 Oct 2016 04:45:18 -0700 Message-Id: <1475322326-160112-2-git-send-email-srinivas.pandruvada@linux.intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1475322326-160112-1-git-send-email-srinivas.pandruvada@linux.intel.com> References: <1475322326-160112-1-git-send-email-srinivas.pandruvada@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5052 Lines: 163 From: Tim Chen We generalize the scheduler's asym packing to provide an ordering of the cpu beyond just the cpu number. This allows the use of the ASYM_PACKING scheduler machinery to move loads to preferred CPU in a sched domain. The preference is defined with the cpu priority given by arch_asym_cpu_priority(cpu). We also record the most preferred cpu in a sched group when we build the cpu's capacity for fast lookup of preferred cpu during load balancing. Signed-off-by: Tim Chen Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Srinivas Pandruvada --- include/linux/sched.h | 2 ++ kernel/sched/core.c | 18 ++++++++++++++++++ kernel/sched/fair.c | 35 ++++++++++++++++++++++++----------- kernel/sched/sched.h | 6 ++++++ 4 files changed, 50 insertions(+), 11 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index 98fe95f..82ca1e4 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1052,6 +1052,8 @@ static inline int cpu_numa_flags(void) } #endif +int arch_asym_cpu_priority(int cpu); + struct sched_domain_attr { int relax_domain_level; }; diff --git a/kernel/sched/core.c b/kernel/sched/core.c index e86c4a5..08135ca 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -6237,7 +6237,25 @@ static void init_sched_groups_capacity(int cpu, struct sched_domain *sd) WARN_ON(!sg); do { + int cpu, max_cpu = -1, prev_cpu = -1; + sg->group_weight = cpumask_weight(sched_group_cpus(sg)); + + if (!(sd->flags & SD_ASYM_PACKING)) + goto next; + + for_each_cpu(cpu, sched_group_cpus(sg)) { + if (prev_cpu < 0) { + prev_cpu = cpu; + max_cpu = cpu; + } else { + if (sched_asym_prefer(cpu, max_cpu)) + max_cpu = cpu; + } + } + sg->asym_prefer_cpu = max_cpu; + +next: sg = sg->next; } while (sg != sd->groups); diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index a5cd07b..bb96e1a 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -100,6 +100,16 @@ const_debug unsigned int sysctl_sched_migration_cost = 500000UL; */ unsigned int __read_mostly sysctl_sched_shares_window = 10000000UL; +#ifdef CONFIG_SMP +/* + * For asym packing, by default the lower numbered cpu has higher priority. + */ +int __weak arch_asym_cpu_priority(int cpu) +{ + return -cpu; +} +#endif + #ifdef CONFIG_CFS_BANDWIDTH /* * Amount of runtime to allocate from global (tg) to local (per-cfs_rq) pool @@ -6861,16 +6871,18 @@ static bool update_sd_pick_busiest(struct lb_env *env, if (env->idle == CPU_NOT_IDLE) return true; /* - * ASYM_PACKING needs to move all the work to the lowest - * numbered CPUs in the group, therefore mark all groups - * higher than ourself as busy. + * ASYM_PACKING needs to move all the work to the highest + * prority CPUs in the group, therefore mark all groups + * of lower priority than ourself as busy. */ - if (sgs->sum_nr_running && env->dst_cpu < group_first_cpu(sg)) { + if (sgs->sum_nr_running && + sched_asym_prefer(env->dst_cpu, sg->asym_prefer_cpu)) { if (!sds->busiest) return true; - /* Prefer to move from highest possible cpu's work */ - if (group_first_cpu(sds->busiest) < group_first_cpu(sg)) + /* Prefer to move from lowest priority cpu's work */ + if (sched_asym_prefer(sds->busiest->asym_prefer_cpu, + sg->asym_prefer_cpu)) return true; } @@ -7022,8 +7034,8 @@ static int check_asym_packing(struct lb_env *env, struct sd_lb_stats *sds) if (!sds->busiest) return 0; - busiest_cpu = group_first_cpu(sds->busiest); - if (env->dst_cpu > busiest_cpu) + busiest_cpu = sds->busiest->asym_prefer_cpu; + if (sched_asym_prefer(busiest_cpu, env->dst_cpu)) return 0; env->imbalance = DIV_ROUND_CLOSEST( @@ -7364,10 +7376,11 @@ static int need_active_balance(struct lb_env *env) /* * ASYM_PACKING needs to force migrate tasks from busy but - * higher numbered CPUs in order to pack all tasks in the - * lowest numbered CPUs. + * lower priority CPUs in order to pack all tasks in the + * highest priority CPUs. */ - if ((sd->flags & SD_ASYM_PACKING) && env->src_cpu > env->dst_cpu) + if ((sd->flags & SD_ASYM_PACKING) && + sched_asym_prefer(env->dst_cpu, env->src_cpu)) return 1; } diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index b7fc1ce..3f3d04a 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -532,6 +532,11 @@ struct dl_rq { #ifdef CONFIG_SMP +static inline bool sched_asym_prefer(int a, int b) +{ + return arch_asym_cpu_priority(a) > arch_asym_cpu_priority(b); +} + /* * We add the notion of a root-domain which will be used to define per-domain * variables. Each exclusive cpuset essentially defines an island domain by @@ -884,6 +889,7 @@ struct sched_group { unsigned int group_weight; struct sched_group_capacity *sgc; + int asym_prefer_cpu; /* cpu of highest priority in group */ /* * The CPUs this group covers. -- 2.7.4