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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 87A4EC07E9D for ; Thu, 29 Sep 2022 07:18:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235180AbiI2HS6 (ORCPT ); Thu, 29 Sep 2022 03:18:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44280 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235148AbiI2HS4 (ORCPT ); Thu, 29 Sep 2022 03:18:56 -0400 Received: from out30-57.freemail.mail.aliyun.com (out30-57.freemail.mail.aliyun.com [115.124.30.57]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 85B52116C2F for ; Thu, 29 Sep 2022 00:18:53 -0700 (PDT) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R951e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018045168;MF=cruzzhao@linux.alibaba.com;NM=1;PH=DS;RN=11;SR=0;TI=SMTPD_---0VQyjp6T_1664435913; Received: from rt2b04371.sqa.tbc.tbsite.net(mailfrom:CruzZhao@linux.alibaba.com fp:SMTPD_---0VQyjp6T_1664435913) by smtp.aliyun-inc.com; Thu, 29 Sep 2022 15:18:50 +0800 From: Cruz Zhao To: mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, vschneid@redhat.com Cc: linux-kernel@vger.kernel.org Subject: [PATCH] sched/core: Optimize the process of picking the max prio task for the core Date: Thu, 29 Sep 2022 15:18:33 +0800 Message-Id: <1664435913-57227-1-git-send-email-CruzZhao@linux.alibaba.com> X-Mailer: git-send-email 1.8.3.1 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When we pick the max prio task for the core in the case of sched_core_enabled(), if there's a task with a higher prio sched class in the runqueue of a SMT, it's not necessary for other SMTs to traverse lower prio sched classes. So we can change the traversal order: for each sched class, if there exists a max prio task among the core, pick it and break the loop. To compare the prio of the tasks with the same sched class, we introduce sched_class::prio_less(). Signed-off-by: Cruz Zhao --- kernel/sched/core.c | 33 ++++++++++++++++++++++----------- kernel/sched/deadline.c | 11 +++++++++++ kernel/sched/fair.c | 5 ++++- kernel/sched/idle.c | 10 ++++++++++ kernel/sched/rt.c | 10 ++++++++++ kernel/sched/sched.h | 5 +++-- kernel/sched/stop_task.c | 10 ++++++++++ 7 files changed, 70 insertions(+), 14 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index a2d8a1f..50e28c8 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -189,7 +189,7 @@ static inline bool prio_less(struct task_struct *a, struct task_struct *b, bool return !dl_time_before(a->dl.deadline, b->dl.deadline); if (pa == MAX_RT_PRIO + MAX_NICE) /* fair */ - return cfs_prio_less(a, b, in_fi); + return fair_sched_class.prio_less(a, b, in_fi); return false; } @@ -5886,6 +5886,7 @@ static inline struct task_struct *pick_task(struct rq *rq) int i, cpu, occ = 0; struct rq *rq_i; bool need_sync; + struct sched_class *class; if (!sched_core_enabled(rq)) return __pick_next_task(rq, prev, rf); @@ -5978,12 +5979,6 @@ static inline struct task_struct *pick_task(struct rq *rq) } } - /* - * For each thread: do the regular task pick and find the max prio task - * amongst them. - * - * Tie-break prio towards the current CPU - */ for_each_cpu_wrap(i, smt_mask, cpu) { rq_i = cpu_rq(i); @@ -5994,12 +5989,28 @@ static inline struct task_struct *pick_task(struct rq *rq) */ if (i != cpu && (rq_i != rq->core || !core_clock_updated)) update_rq_clock(rq_i); + } - p = rq_i->core_pick = pick_task(rq_i); - if (!max || prio_less(max, p, fi_before)) - max = p; + /* + * For each thread: do the regular task pick and find the max prio task + * amongst them. + * + * Tie-break prio towards the current CPU + */ + for_each_class(class) { + for_each_cpu_wrap(i, smt_mask, cpu) { + rq_i = cpu_rq(i); + p = rq_i->core_pick = class->pick_task(rq_i); + if (!max || (p && class->prio_less(max, p, fi_before))) + max = p; + } + if (max) + break; } + if (!max) + BUG(); + cookie = rq->core->core_cookie = max->core_cookie; /* @@ -6010,7 +6021,7 @@ static inline struct task_struct *pick_task(struct rq *rq) rq_i = cpu_rq(i); p = rq_i->core_pick; - if (!cookie_equals(p, cookie)) { + if (!p || !cookie_equals(p, cookie)) { p = NULL; if (cookie) p = sched_core_find(rq_i, cookie); diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index 86dea6a..8e7aa7d 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -1942,6 +1942,7 @@ static int balance_dl(struct rq *rq, struct task_struct *p, struct rq_flags *rf) return sched_stop_runnable(rq) || sched_dl_runnable(rq); } + #endif /* CONFIG_SMP */ /* @@ -2054,6 +2055,13 @@ static void put_prev_task_dl(struct rq *rq, struct task_struct *p) enqueue_pushable_dl_task(rq, p); } +#ifdef CONFIG_SCHED_CORE +static bool prio_less_dl(struct task_struct *a, struct task_struct *b, bool in_fi) +{ + return !dl_time_before(a->dl.deadline, b->dl.deadline); +} +#endif + /* * scheduler tick hitting a task of our scheduling class. * @@ -2704,6 +2712,9 @@ static void prio_changed_dl(struct rq *rq, struct task_struct *p, .pick_next_task = pick_next_task_dl, .put_prev_task = put_prev_task_dl, .set_next_task = set_next_task_dl, +#ifdef CONFIG_SCHED_CORE + .prio_less = prio_less_dl, +#endif #ifdef CONFIG_SMP .balance = balance_dl, diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index e4a0b8b..eca2636 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -11516,7 +11516,7 @@ void task_vruntime_update(struct rq *rq, struct task_struct *p, bool in_fi) se_fi_update(se, rq->core->core_forceidle_seq, in_fi); } -bool cfs_prio_less(struct task_struct *a, struct task_struct *b, bool in_fi) +static bool prio_less_fair(struct task_struct *a, struct task_struct *b, bool in_fi) { struct rq *rq = task_rq(a); struct sched_entity *sea = &a->se; @@ -12159,6 +12159,9 @@ static unsigned int get_rr_interval_fair(struct rq *rq, struct task_struct *task .pick_next_task = __pick_next_task_fair, .put_prev_task = put_prev_task_fair, .set_next_task = set_next_task_fair, +#ifdef CONFIG_SCHED_CORE + .prio_less = prio_less_fair, +#endif #ifdef CONFIG_SMP .balance = balance_fair, diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c index f26ab26..a3c3e37 100644 --- a/kernel/sched/idle.c +++ b/kernel/sched/idle.c @@ -436,6 +436,13 @@ static void set_next_task_idle(struct rq *rq, struct task_struct *next, bool fir schedstat_inc(rq->sched_goidle); } +#ifdef CONFIG_SCHED_CORE +static bool prio_less_idle(struct task_struct *a, struct task_struct *b, bool in_fi) +{ + return false; +} +#endif + #ifdef CONFIG_SMP static struct task_struct *pick_task_idle(struct rq *rq) { @@ -507,6 +514,9 @@ static void update_curr_idle(struct rq *rq) .pick_next_task = pick_next_task_idle, .put_prev_task = put_prev_task_idle, .set_next_task = set_next_task_idle, +#ifdef CONFIG_SCHED_CORE + .prio_less = prio_less_idle, +#endif #ifdef CONFIG_SMP .balance = balance_idle, diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index d869bcf..4459a90 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -1838,6 +1838,13 @@ static void put_prev_task_rt(struct rq *rq, struct task_struct *p) enqueue_pushable_task(rq, p); } +static bool prio_less_rt(struct task_struct *a, struct task_struct *b, bool in_fi) +{ + int pa = rt_prio(a->prio), pb = rt_prio(b->prio); + + return -pa < -pb; +} + #ifdef CONFIG_SMP /* Only try algorithms three times */ @@ -2685,6 +2692,9 @@ static unsigned int get_rr_interval_rt(struct rq *rq, struct task_struct *task) .pick_next_task = pick_next_task_rt, .put_prev_task = put_prev_task_rt, .set_next_task = set_next_task_rt, +#ifdef CONFIG_SCHED_CORE + .prio_less = prio_less_rt, +#endif #ifdef CONFIG_SMP .balance = balance_rt, diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 1644242..6d8055c 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1218,8 +1218,6 @@ static inline raw_spinlock_t *__rq_lockp(struct rq *rq) return &rq->__lock; } -bool cfs_prio_less(struct task_struct *a, struct task_struct *b, bool fi); - /* * Helpers to check if the CPU's core cookie matches with the task's cookie * when core scheduling is enabled. @@ -2155,6 +2153,9 @@ struct sched_class { void (*put_prev_task)(struct rq *rq, struct task_struct *p); void (*set_next_task)(struct rq *rq, struct task_struct *p, bool first); +#ifdef CONFIG_SCHED_CORE + bool prio_less(struct task_struct *a, struct task_struct *b, bool in_fi); +#endif #ifdef CONFIG_SMP int (*balance)(struct rq *rq, struct task_struct *prev, struct rq_flags *rf); diff --git a/kernel/sched/stop_task.c b/kernel/sched/stop_task.c index 8559059..c9ddaaa 100644 --- a/kernel/sched/stop_task.c +++ b/kernel/sched/stop_task.c @@ -84,6 +84,13 @@ static void put_prev_task_stop(struct rq *rq, struct task_struct *prev) update_current_exec_runtime(curr, now, delta_exec); } +#ifdef CONFIG_SCHED_CORE +static bool prio_less_stop(struct task_struct *a, struct task_struct *b, bool in_fi) +{ + return false; +} +#endif + /* * scheduler tick hitting a task of our scheduling class. * @@ -125,6 +132,9 @@ static void update_curr_stop(struct rq *rq) .pick_next_task = pick_next_task_stop, .put_prev_task = put_prev_task_stop, .set_next_task = set_next_task_stop, +#ifdef CONFIG_SCHED_CORE + .prio_less = prio_less_stop, +#endif #ifdef CONFIG_SMP .balance = balance_stop, -- 1.8.3.1