Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Mon, 15 Aug 2022 15:23:30 +0200
From:   Michal =?iso-8859-1?Q?Koutn=FD?= <mkoutny@suse.com>
To:     Chengming Zhou <zhouchengming@bytedance.com>
Cc:     hannes@cmpxchg.org, tj@kernel.org, corbet@lwn.net,
        surenb@google.com, mingo@redhat.com, peterz@infradead.org,
        vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
        rostedt@goodmis.org, bsegall@google.com, cgroups@vger.kernel.org,
        linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
        songmuchun@bytedance.com
Subject: Re: [PATCH v2 09/10] sched/psi: per-cgroup PSI stats
 disable/re-enable interface
Message-ID: <20220815132330.GA24237@blackbody.suse.cz>
References: <20220808110341.15799-1-zhouchengming@bytedance.com>
 <20220808110341.15799-10-zhouchengming@bytedance.com>
 <YvYoFNDMdg6mdFbU@blackbook>
 <5ce118b3-bf3b-d9a4-004c-a5a355984b0f@bytedance.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <5ce118b3-bf3b-d9a4-004c-a5a355984b0f@bytedance.com>
User-Agent: Mutt/1.10.1 (2018-07-13)
Precedence: bulk

On Fri, Aug 12, 2022 at 08:36:17PM +0800, Chengming Zhou <zhouchengming@bytedance.com> wrote:
> Could you help take a look if there is anything to improve?

Thanks, just a little nit.

> +       The reason this control attribute exists is that PSI accounts stalls for
> +       each cgroup separately and aggregates it at each level of the hierarchy.
> +       This may cause non-negligible overhead for some workloads when under
> +       deep level of the hierarchy, in which case this control attribute can
> +       be used to disable PSI accounting in the cgroups.

s/in the cgroups/in the non-leaf cgroups/
or
s/in the cgroups/in the uninteresting cgroups/

(I'm concerned that it may result in lots of disabling if you want the
performance. I'll expand on it in 2nd subthread.)

Michal