Re: [PATCH] sched/Documentation: Add RT_RUNTIME_SHARE documentation

[Zhang Qiao <zhangqiao22@huawei.com>]

在 2024/4/12 10:50, Bagas Sanjaya 写道:
> On Wed, Jan 31, 2024 at 08:32:38PM +0800, Zhang Qiao wrote:
>> +2.4 RT_RUNTIME_SHARE sched feature
>> +----------------------------
> 
> htmldocs build reports new warning:
> 
> Documentation/scheduler/sched-rt-group.rst:151: WARNING: Title underline too short.
> 
> 2.4 RT_RUNTIME_SHARE sched feature
> ----------------------------
> 
> I have to extend the underline:
> 
> ---- >8 ----
> diff --git a/Documentation/scheduler/sched-rt-group.rst b/Documentation/scheduler/sched-rt-group.rst
> index 4d8eceb71f5ed8..751113fcd35850 100644
> --- a/Documentation/scheduler/sched-rt-group.rst
> +++ b/Documentation/scheduler/sched-rt-group.rst
> @@ -148,7 +148,7 @@ For now, this can be simplified to just the following (but see Future plans):
>     \Sum_{i} runtime_{i} <= global_runtime
>  
>  2.4 RT_RUNTIME_SHARE sched feature
> -----------------------------
> +----------------------------------
>  
>  RT_RUNTIME_SHARE allows a cpu borrows rt-runtime from other cpus if it runs
>  out of its own rt-runtime.
> 
> Wording suggestions below.

Hi, Bagas，
Thanks for you suggestions, i will update in v2.


Zhang Qiao.

> 
>> +
>> +RT_RUNTIME_SHARE allows a cpu borrows rt-runtime from other cpus if it runs
> "... to borrow rt-runtime ..."
>> +out of its own rt-runtime.
>> +
>> +With this feature enabled, a rt-task probably hits 100% cpu usage and starves
> "... a rt-task may hit ... and can stall other per-cpu tasks ..."
>> +per-cpu tasks like kworkers, as a result, it may hang up the whole system.
> "..., which lead into system hang."
>> +Therefore, in order to avoid such exception, recommand to disable this feature
>> +by default unless you really know what you're up to.
> "Thus, it is advised to disable this feature by default to avoid aforementioned
> issue unless you know what you're doing."
> 
> Thanks.
>