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Date:   Wed, 22 Jun 2022 19:39:29 +0200
From:   Michal =?iso-8859-1?Q?Koutn=FD?= <mkoutny@suse.com>
To:     Chengming Zhou <zhouchengming@bytedance.com>
Cc:     rdunlap@infradead.org, mingo@redhat.com, peterz@infradead.org,
        juri.lelli@redhat.com, vincent.guittot@linaro.org,
        dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com,
        tj@kernel.org, lizefan.x@bytedance.com, hannes@cmpxchg.org,
        corbet@lwn.net, cgroups@vger.kernel.org, linux-doc@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] sched: RT bandwidth interface for cgroup unified
 hierarchy
Message-ID: <20220622173929.GA669@blackbody.suse.cz>
References: <20220622015557.7497-1-zhouchengming@bytedance.com>
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Hello Chengming.

On Wed, Jun 22, 2022 at 09:55:57AM +0800, Chengming Zhou <zhouchengming@bytedance.com> wrote:
> We need to run RT threads in cgroup unified hierarchy, but we can't
> since the default rt_bandwidth.rt_runtime of non-root task_group is 0
> and we haven't interface to update it.

Do you really want to make use of group RT schedulling
(CONFIG_RT_GROUP_SCHED) or just be able to run RT threads in the unified
hieararchy with cpu controller enabled?

Those are two different use cases, the former is more complex and it's a
reason why v2 doesn't expose the RT attributes (yet).
The latter is typically achieved by unsetting CONFIG_RT_GROUP_SCHED (and
relying on the global rt_runtime limit).

Thanks,
Michal