From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4D574C432BE for ; Tue, 31 Aug 2021 10:44:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 26A6360F23 for ; Tue, 31 Aug 2021 10:44:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241176AbhHaKpu (ORCPT ); Tue, 31 Aug 2021 06:45:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40752 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238567AbhHaKpt (ORCPT ); Tue, 31 Aug 2021 06:45:49 -0400 Received: from desiato.infradead.org (desiato.infradead.org [IPv6:2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A82D6C061575; Tue, 31 Aug 2021 03:44:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=fcq0Vj8dz4GfpImmXhE/w+/OCqqc9iyFgNrysUGvKgY=; b=rFZhxj9FaxRd5jlpzADAkSh+FQ 2T2vZQCrxN6sH/vERrmZzU6bZ3+Mu4B3Fh6cGRpn5e0rVrW0huU9Gh0eiOtnVAc6gnp4venls+6Bk Mor7TBXFEW46m+nsJolC0zEifUguyCetEZSceLkjrqVBzuQ50Br03kMaT0+jGTsEhgvU6m5u+sAtd hpbqxcAwF46mm2zKsGaW6vQzgpYgfLpCYQ7iJBBO+OwfsQY7M1Z9Mx4+G1mdYdQ9tQ57dGX2eJ/Qp IzNDXj9iXOX9A9d0GWWOX7VEntc0TzoreZyDCrH3Qkeu1MJcmP6PVs7eoeYdx5V/jnR6qvZqYOeZs xG34pQKA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1mL1Fs-00Eg7q-Sc; Tue, 31 Aug 2021 10:44:37 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id AFF73300109; Tue, 31 Aug 2021 12:44:35 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 904732C7E2CC8; Tue, 31 Aug 2021 12:44:35 +0200 (CEST) Date: Tue, 31 Aug 2021 12:44:35 +0200 From: Peter Zijlstra To: Yafang Shao Cc: mingo@redhat.com, mgorman@suse.de, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, bristot@redhat.com, achaiken@aurora.tech, lkp@intel.com, linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org Subject: Re: [PATCH v3 0/7] sched: support schedstats for RT sched class Message-ID: References: <20210824112946.9324-1-laoar.shao@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-rt-users@vger.kernel.org On Tue, Aug 31, 2021 at 12:08:15PM +0200, Peter Zijlstra wrote: > On Tue, Aug 24, 2021 at 11:29:39AM +0000, Yafang Shao wrote: > > After the patchset, schestats are orgnized as follows, > > struct task_struct { > > ... > > struct sched_statistics statistics; > > ... > > struct sched_entity *se; > > struct sched_rt_entity *rt; > > ... > > }; > > > > struct task_group { |---> stats[0] : of CPU0 > > ... | > > struct sched_statistics **stats; --|---> stats[1] : of CPU1 > > ... | > > |---> stats[n] : of CPUn > > #ifdef CONFIG_FAIR_GROUP_SCHED > > struct sched_entity **se; > > #endif > > #ifdef CONFIG_RT_GROUP_SCHED > > struct sched_rt_entity **rt_se; > > #endif > > ... > > }; > > Yeah, this seems to give a terrible mess, let me see if I can come up > with anything less horrible. Here, isn't this *MUCH* saner ? --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -521,7 +521,7 @@ struct sched_statistics { u64 nr_wakeups_passive; u64 nr_wakeups_idle; #endif -}; +} ____cacheline_aligned; struct sched_entity { /* For load-balancing: */ @@ -537,8 +537,6 @@ struct sched_entity { u64 nr_migrations; - struct sched_statistics statistics; - #ifdef CONFIG_FAIR_GROUP_SCHED int depth; struct sched_entity *parent; @@ -802,6 +800,8 @@ struct task_struct { struct uclamp_se uclamp[UCLAMP_CNT]; #endif + struct sched_statistics stats; + #ifdef CONFIG_PREEMPT_NOTIFIERS /* List of struct preempt_notifier: */ struct hlist_head preempt_notifiers; --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -3489,11 +3489,11 @@ ttwu_stat(struct task_struct *p, int cpu #ifdef CONFIG_SMP if (cpu == rq->cpu) { __schedstat_inc(rq->ttwu_local); - __schedstat_inc(p->se.statistics.nr_wakeups_local); + __schedstat_inc(p->stats.nr_wakeups_local); } else { struct sched_domain *sd; - __schedstat_inc(p->se.statistics.nr_wakeups_remote); + __schedstat_inc(p->stats.nr_wakeups_remote); rcu_read_lock(); for_each_domain(rq->cpu, sd) { if (cpumask_test_cpu(cpu, sched_domain_span(sd))) { @@ -3505,14 +3505,14 @@ ttwu_stat(struct task_struct *p, int cpu } if (wake_flags & WF_MIGRATED) - __schedstat_inc(p->se.statistics.nr_wakeups_migrate); + __schedstat_inc(p->stats.nr_wakeups_migrate); #endif /* CONFIG_SMP */ __schedstat_inc(rq->ttwu_count); - __schedstat_inc(p->se.statistics.nr_wakeups); + __schedstat_inc(p->stats.nr_wakeups); if (wake_flags & WF_SYNC) - __schedstat_inc(p->se.statistics.nr_wakeups_sync); + __schedstat_inc(p->stats.nr_wakeups_sync); } /* @@ -4196,7 +4196,7 @@ static void __sched_fork(unsigned long c #ifdef CONFIG_SCHEDSTATS /* Even if schedstat is disabled, there should not be garbage */ - memset(&p->se.statistics, 0, sizeof(p->se.statistics)); + memset(&p->stats, 0, sizeof(p->stats)); #endif RB_CLEAR_NODE(&p->dl.rb_node); @@ -9619,9 +9619,9 @@ void normalize_rt_tasks(void) continue; p->se.exec_start = 0; - schedstat_set(p->se.statistics.wait_start, 0); - schedstat_set(p->se.statistics.sleep_start, 0); - schedstat_set(p->se.statistics.block_start, 0); + schedstat_set(p->stats.wait_start, 0); + schedstat_set(p->stats.sleep_start, 0); + schedstat_set(p->stats.block_start, 0); if (!dl_task(p) && !rt_task(p)) { /* @@ -10467,7 +10467,7 @@ static int cpu_cfs_stat_show(struct seq_ int i; for_each_possible_cpu(i) - ws += schedstat_val(tg->se[i]->statistics.wait_sum); + ws += schedstat_val(tg->stats[i]->wait_sum); seq_printf(sf, "wait_sum %llu\n", ws); } --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -1265,8 +1265,8 @@ static void update_curr_dl(struct rq *rq return; } - schedstat_set(curr->se.statistics.exec_max, - max(curr->se.statistics.exec_max, delta_exec)); + schedstat_set(curr->stats.exec_max, + max(curr->stats.exec_max, delta_exec)); curr->se.sum_exec_runtime += delta_exec; account_group_exec_runtime(curr, delta_exec); --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -819,6 +819,21 @@ static void update_tg_load_avg(struct cf } #endif /* CONFIG_SMP */ +struct sched_entity_stats { + struct sched_entity se; + struct sched_statistics stats; +} __no_randomize_layout; + +static inline struct sched_statistics * +__schedstats_from_se(struct sched_entity *se) +{ +#ifdef CONFIG_FAIR_GROUP_SCHED + if (!entity_is_task(se)) + return &container_of(se, struct sched_entity_stats, se)->stats; +#endif + return &task_of(se)->stats; +} + /* * Update the current task's runtime statistics. */ @@ -837,8 +852,10 @@ static void update_curr(struct cfs_rq *c curr->exec_start = now; - schedstat_set(curr->statistics.exec_max, - max(delta_exec, curr->statistics.exec_max)); + if (schedstat_enabled()) { + struct sched_statistics *stats = __schedstats_from_se(curr); + __schedstat_set(stats->exec_max, max(delta_exec, stats->exec_max)); + } curr->sum_exec_runtime += delta_exec; schedstat_add(cfs_rq->exec_clock, delta_exec); @@ -866,39 +883,45 @@ static inline void update_stats_wait_start(struct cfs_rq *cfs_rq, struct sched_entity *se) { u64 wait_start, prev_wait_start; + struct sched_statistics *stats; if (!schedstat_enabled()) return; + stats = __schedstats_from_se(se); + wait_start = rq_clock(rq_of(cfs_rq)); - prev_wait_start = schedstat_val(se->statistics.wait_start); + prev_wait_start = schedstat_val(stats->wait_start); if (entity_is_task(se) && task_on_rq_migrating(task_of(se)) && likely(wait_start > prev_wait_start)) wait_start -= prev_wait_start; - __schedstat_set(se->statistics.wait_start, wait_start); + __schedstat_set(stats->wait_start, wait_start); } static inline void update_stats_wait_end(struct cfs_rq *cfs_rq, struct sched_entity *se) { - struct task_struct *p; + struct sched_statistics *stats; + struct task_struct *p = NULL; u64 delta; if (!schedstat_enabled()) return; + stats = __schedstats_from_se(se); + /* * When the sched_schedstat changes from 0 to 1, some sched se * maybe already in the runqueue, the se->statistics.wait_start * will be 0.So it will let the delta wrong. We need to avoid this * scenario. */ - if (unlikely(!schedstat_val(se->statistics.wait_start))) + if (unlikely(!schedstat_val(stats->wait_start))) return; - delta = rq_clock(rq_of(cfs_rq)) - schedstat_val(se->statistics.wait_start); + delta = rq_clock(rq_of(cfs_rq)) - schedstat_val(stats->wait_start); if (entity_is_task(se)) { p = task_of(se); @@ -908,30 +931,33 @@ update_stats_wait_end(struct cfs_rq *cfs * time stamp can be adjusted to accumulate wait time * prior to migration. */ - __schedstat_set(se->statistics.wait_start, delta); + __schedstat_set(stats->wait_start, delta); return; } trace_sched_stat_wait(p, delta); } - __schedstat_set(se->statistics.wait_max, - max(schedstat_val(se->statistics.wait_max), delta)); - __schedstat_inc(se->statistics.wait_count); - __schedstat_add(se->statistics.wait_sum, delta); - __schedstat_set(se->statistics.wait_start, 0); + __schedstat_set(stats->wait_max, + max(schedstat_val(stats->wait_max), delta)); + __schedstat_inc(stats->wait_count); + __schedstat_add(stats->wait_sum, delta); + __schedstat_set(stats->wait_start, 0); } static inline void update_stats_enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se) { + struct sched_statistics *stats; struct task_struct *tsk = NULL; u64 sleep_start, block_start; if (!schedstat_enabled()) return; - sleep_start = schedstat_val(se->statistics.sleep_start); - block_start = schedstat_val(se->statistics.block_start); + stats = __schedstats_from_se(se); + + sleep_start = schedstat_val(stats->sleep_start); + block_start = schedstat_val(stats->block_start); if (entity_is_task(se)) tsk = task_of(se); @@ -942,11 +968,11 @@ update_stats_enqueue_sleeper(struct cfs_ if ((s64)delta < 0) delta = 0; - if (unlikely(delta > schedstat_val(se->statistics.sleep_max))) - __schedstat_set(se->statistics.sleep_max, delta); + if (unlikely(delta > schedstat_val(stats->sleep_max))) + __schedstat_set(stats->sleep_max, delta); - __schedstat_set(se->statistics.sleep_start, 0); - __schedstat_add(se->statistics.sum_sleep_runtime, delta); + __schedstat_set(stats->sleep_start, 0); + __schedstat_add(stats->sum_sleep_runtime, delta); if (tsk) { account_scheduler_latency(tsk, delta >> 10, 1); @@ -959,16 +985,16 @@ update_stats_enqueue_sleeper(struct cfs_ if ((s64)delta < 0) delta = 0; - if (unlikely(delta > schedstat_val(se->statistics.block_max))) - __schedstat_set(se->statistics.block_max, delta); + if (unlikely(delta > schedstat_val(stats->block_max))) + __schedstat_set(stats->block_max, delta); - __schedstat_set(se->statistics.block_start, 0); - __schedstat_add(se->statistics.sum_sleep_runtime, delta); + __schedstat_set(stats->block_start, 0); + __schedstat_add(stats->sum_sleep_runtime, delta); if (tsk) { if (tsk->in_iowait) { - __schedstat_add(se->statistics.iowait_sum, delta); - __schedstat_inc(se->statistics.iowait_count); + __schedstat_add(stats->iowait_sum, delta); + __schedstat_inc(stats->iowait_count); trace_sched_stat_iowait(tsk, delta); } @@ -1030,10 +1056,10 @@ update_stats_dequeue(struct cfs_rq *cfs_ /* XXX racy against TTWU */ state = READ_ONCE(tsk->__state); if (state & TASK_INTERRUPTIBLE) - __schedstat_set(se->statistics.sleep_start, + __schedstat_set(tsk->stats.sleep_start, rq_clock(rq_of(cfs_rq))); if (state & TASK_UNINTERRUPTIBLE) - __schedstat_set(se->statistics.block_start, + __schedstat_set(tsk->stats.block_start, rq_clock(rq_of(cfs_rq))); } } @@ -4502,9 +4528,10 @@ set_next_entity(struct cfs_rq *cfs_rq, s */ if (schedstat_enabled() && rq_of(cfs_rq)->cfs.load.weight >= 2*se->load.weight) { - __schedstat_set(se->statistics.slice_max, - max((u64)schedstat_val(se->statistics.slice_max), - se->sum_exec_runtime - se->prev_sum_exec_runtime)); + struct sched_statistics *stats = __schedstats_from_se(se); + __schedstat_set(stats->slice_max, + max((u64)stats->slice_max, + se->sum_exec_runtime - se->prev_sum_exec_runtime)); } se->prev_sum_exec_runtime = se->sum_exec_runtime; @@ -5993,12 +6020,12 @@ static int wake_affine(struct sched_doma if (sched_feat(WA_WEIGHT) && target == nr_cpumask_bits) target = wake_affine_weight(sd, p, this_cpu, prev_cpu, sync); - schedstat_inc(p->se.statistics.nr_wakeups_affine_attempts); + schedstat_inc(p->stats.nr_wakeups_affine_attempts); if (target == nr_cpumask_bits) return prev_cpu; schedstat_inc(sd->ttwu_move_affine); - schedstat_inc(p->se.statistics.nr_wakeups_affine); + schedstat_inc(p->stats.nr_wakeups_affine); return target; } @@ -7802,7 +7829,7 @@ int can_migrate_task(struct task_struct if (!cpumask_test_cpu(env->dst_cpu, p->cpus_ptr)) { int cpu; - schedstat_inc(p->se.statistics.nr_failed_migrations_affine); + schedstat_inc(p->stats.nr_failed_migrations_affine); env->flags |= LBF_SOME_PINNED; @@ -7836,7 +7863,7 @@ int can_migrate_task(struct task_struct env->flags &= ~LBF_ALL_PINNED; if (task_running(env->src_rq, p)) { - schedstat_inc(p->se.statistics.nr_failed_migrations_running); + schedstat_inc(p->stats.nr_failed_migrations_running); return 0; } @@ -7858,12 +7885,12 @@ int can_migrate_task(struct task_struct env->sd->nr_balance_failed > env->sd->cache_nice_tries) { if (tsk_cache_hot == 1) { schedstat_inc(env->sd->lb_hot_gained[env->idle]); - schedstat_inc(p->se.statistics.nr_forced_migrations); + schedstat_inc(p->stats.nr_forced_migrations); } return 1; } - schedstat_inc(p->se.statistics.nr_failed_migrations_hot); + schedstat_inc(p->stats.nr_failed_migrations_hot); return 0; } @@ -11390,7 +11417,7 @@ int alloc_fair_sched_group(struct task_g if (!cfs_rq) goto err; - se = kzalloc_node(sizeof(struct sched_entity), + se = kzalloc_node(sizeof(struct sched_entity_stats), GFP_KERNEL, cpu_to_node(i)); if (!se) goto err_free_rq; --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -1009,8 +1009,8 @@ static void update_curr_rt(struct rq *rq if (unlikely((s64)delta_exec <= 0)) return; - schedstat_set(curr->se.statistics.exec_max, - max(curr->se.statistics.exec_max, delta_exec)); + schedstat_set(curr->stats.exec_max, + max(curr->stats.exec_max, delta_exec)); curr->se.sum_exec_runtime += delta_exec; account_group_exec_runtime(curr, delta_exec); --- a/kernel/sched/stats.h +++ b/kernel/sched/stats.h @@ -41,6 +41,7 @@ rq_sched_info_dequeue(struct rq *rq, uns #define schedstat_val_or_zero(var) ((schedstat_enabled()) ? (var) : 0) #else /* !CONFIG_SCHEDSTATS: */ + static inline void rq_sched_info_arrive (struct rq *rq, unsigned long long delta) { } static inline void rq_sched_info_dequeue(struct rq *rq, unsigned long long delta) { } static inline void rq_sched_info_depart (struct rq *rq, unsigned long long delta) { } @@ -53,6 +54,7 @@ static inline void rq_sched_info_depart # define schedstat_set(var, val) do { } while (0) # define schedstat_val(var) 0 # define schedstat_val_or_zero(var) 0 + #endif /* CONFIG_SCHEDSTATS */ #ifdef CONFIG_PSI --- a/kernel/sched/stop_task.c +++ b/kernel/sched/stop_task.c @@ -78,8 +78,8 @@ static void put_prev_task_stop(struct rq if (unlikely((s64)delta_exec < 0)) delta_exec = 0; - schedstat_set(curr->se.statistics.exec_max, - max(curr->se.statistics.exec_max, delta_exec)); + schedstat_set(curr->stats.exec_max, + max(curr->stats.exec_max, delta_exec)); curr->se.sum_exec_runtime += delta_exec; account_group_exec_runtime(curr, delta_exec);