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Message-ID: <65d9f79b-be9b-e21e-0624-5c9f2cc0c0b2@bytedance.com>
Date:   Fri, 22 Jul 2022 11:30:53 +0800
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Subject: Re: [PATCH 9/9] sched/psi: add PSI_IRQ to track IRQ/SOFTIRQ pressure
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To:     Chengming Zhou <zhouchengming@bytedance.com>, hannes@cmpxchg.org,
        surenb@google.com, mingo@redhat.com, peterz@infradead.org,
        tj@kernel.org, corbet@lwn.net, akpm@linux-foundation.org,
        rdunlap@infradead.org
Cc:     linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
        songmuchun@bytedance.com, cgroups@vger.kernel.org
References: <20220721040439.2651-1-zhouchengming@bytedance.com>
 <20220721040439.2651-10-zhouchengming@bytedance.com>
From:   Abel Wu <wuyun.abel@bytedance.com>
In-Reply-To: <20220721040439.2651-10-zhouchengming@bytedance.com>
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Hi Chengming,

On 7/21/22 12:04 PM, Chengming Zhou Wrote:
> Now PSI already tracked workload pressure stall information for
> CPU, memory and IO. Apart from these, IRQ/SOFTIRQ could have
> obvious impact on some workload productivity, such as web service
> workload.
> 
> When CONFIG_IRQ_TIME_ACCOUNTING, we can get IRQ/SOFTIRQ delta time
> from update_rq_clock_task(), in which we can record that delta
> to CPU curr task's cgroups as PSI_IRQ_FULL status.

The {soft,}irq affection should be equal to all the runnable tasks
on that cpu, not only rq->curr. Further I think irqstall is per-cpu
rather than per-cgroup.

Abel