From: Peter Zijlstra <peterz@infradead.org>
To: Yicong Yang <yangyicong@huawei.com>
Cc: mingo@redhat.com, juri.lelli@redhat.com,
vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
tim.c.chen@linux.intel.com, yu.c.chen@intel.com,
gautham.shenoy@amd.com, mgorman@suse.de, vschneid@redhat.com,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, rostedt@goodmis.org,
bsegall@google.com, bristot@redhat.com, prime.zeng@huawei.com,
yangyicong@hisilicon.com, jonathan.cameron@huawei.com,
ego@linux.vnet.ibm.com, srikar@linux.vnet.ibm.com,
linuxarm@huawei.com, 21cnbao@gmail.com, kprateek.nayak@amd.com,
wuyun.abel@bytedance.com
Subject: Re: [PATCH v11 2/3] sched/fair: Scan cluster before scanning LLC in wake-up path
Date: Fri, 20 Oct 2023 15:41:30 +0200 [thread overview]
Message-ID: <20231020134130.GC33965@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <20231019033323.54147-3-yangyicong@huawei.com>
On Thu, Oct 19, 2023 at 11:33:22AM +0800, Yicong Yang wrote:
> @@ -7349,8 +7373,13 @@ static int select_idle_sibling(struct task_struct *p, int prev, int target)
> */
> if (prev != target && cpus_share_cache(prev, target) &&
> (available_idle_cpu(prev) || sched_idle_cpu(prev)) &&
> - asym_fits_cpu(task_util, util_min, util_max, prev))
> - return prev;
> + asym_fits_cpu(task_util, util_min, util_max, prev)) {
> + if (!static_branch_unlikely(&sched_cluster_active))
> + return prev;
> +
> + if (cpus_share_resources(prev, target))
> + return prev;
> + }
>
> /*
> * Allow a per-cpu kthread to stack with the wakee if the
> @@ -7377,7 +7406,11 @@ static int select_idle_sibling(struct task_struct *p, int prev, int target)
> (available_idle_cpu(recent_used_cpu) || sched_idle_cpu(recent_used_cpu)) &&
> cpumask_test_cpu(recent_used_cpu, p->cpus_ptr) &&
> asym_fits_cpu(task_util, util_min, util_max, recent_used_cpu)) {
> - return recent_used_cpu;
> + if (!static_branch_unlikely(&sched_cluster_active))
> + return recent_used_cpu;
> +
> + if (cpus_share_resources(recent_used_cpu, target))
> + return recent_used_cpu;
> }
>
> /*
I've changed those like so:
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -7420,10 +7420,9 @@ static int select_idle_sibling(struct ta
if (prev != target && cpus_share_cache(prev, target) &&
(available_idle_cpu(prev) || sched_idle_cpu(prev)) &&
asym_fits_cpu(task_util, util_min, util_max, prev)) {
- if (!static_branch_unlikely(&sched_cluster_active))
- return prev;
- if (cpus_share_resources(prev, target))
+ if (!static_branch_unlikely(&sched_cluster_active) ||
+ cpus_share_resources(prev, target))
return prev;
}
@@ -7452,11 +7451,11 @@ static int select_idle_sibling(struct ta
(available_idle_cpu(recent_used_cpu) || sched_idle_cpu(recent_used_cpu)) &&
cpumask_test_cpu(recent_used_cpu, p->cpus_ptr) &&
asym_fits_cpu(task_util, util_min, util_max, recent_used_cpu)) {
- if (!static_branch_unlikely(&sched_cluster_active))
- return recent_used_cpu;
- if (cpus_share_resources(recent_used_cpu, target))
+ if (!static_branch_unlikely(&sched_cluster_active) ||
+ cpus_share_resources(recent_used_cpu, target))
return recent_used_cpu;
+
}
/*
next prev parent reply other threads:[~2023-10-20 13:42 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-19 3:33 [PATCH v11 0/3] sched/fair: Scan cluster before scanning LLC in wake-up path Yicong Yang
2023-10-19 3:33 ` [PATCH v11 1/3] sched: Add cpus_share_resources API Yicong Yang
2023-10-24 8:52 ` [tip: sched/core] " tip-bot2 for Barry Song
2023-10-19 3:33 ` [PATCH v11 2/3] sched/fair: Scan cluster before scanning LLC in wake-up path Yicong Yang
2023-10-20 13:41 ` Peter Zijlstra [this message]
2023-10-24 8:52 ` [tip: sched/core] " tip-bot2 for Barry Song
2023-10-19 3:33 ` [PATCH v11 3/3] sched/fair: Use candidate prev/recent_used CPU if scanning failed for cluster wakeup Yicong Yang
2023-10-19 12:08 ` Vincent Guittot
2023-10-20 7:36 ` Chen Yu
2023-10-24 8:52 ` [tip: sched/core] " tip-bot2 for Yicong Yang
2023-10-20 13:43 ` [PATCH] sched/fair: Remove SIS_PROP Peter Zijlstra
2023-10-20 14:23 ` Vincent Guittot
2023-10-23 3:55 ` Yicong Yang
2023-10-23 8:42 ` Mel Gorman
2023-10-24 8:52 ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
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