[PATCH v2] sched/Documentation: Add RT_RUNTIME_SHARE documentation

[PATCH v2] sched/Documentation: Add RT_RUNTIME_SHARE documentation

[Zhang Qiao]

RT_RUNTIME_SHARE is an important strategy for rt bandwidth, and
we should document this sched feature.

Signed-off-by: Zhang Qiao <zhangqiao22@huawei.com>
Improvements-suggested-by: Bagas Sanjaya <bagasdotme@gmail.com>
---
 Documentation/scheduler/sched-rt-group.rst | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/Documentation/scheduler/sched-rt-group.rst b/Documentation/scheduler/sched-rt-group.rst
index d685609ed3d7..eea2fc6f068f 100644
--- a/Documentation/scheduler/sched-rt-group.rst
+++ b/Documentation/scheduler/sched-rt-group.rst
@@ -12,6 +12,7 @@ Real-Time group scheduling
      2.1 System-wide settings
      2.2 Default behaviour
      2.3 Basis for grouping tasks
+     2.4 RT_RUNTIME_SHARE sched feature
    3. Future plans
 
 
@@ -146,6 +147,17 @@ 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 to borrow rt-runtime from other cpus if it runs
+out of its own rt-runtime.
+
+With this feature enabled, a rt-task may hit 100% cpu usage and can stall other
+per-cpu tasks like kworkers, as a result, which leads into system hang.
+
+Thus, it is advised to disable this feature by default to avoid aforementioned
+issue unless you know what you're doing.
 
 3. Future plans
 ===============
-- 
2.18.0.huawei.25

Re: [PATCH v2] sched/Documentation: Add RT_RUNTIME_SHARE documentation

[Bagas Sanjaya]

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On Fri, Apr 19, 2024 at 05:04:32PM +0800, Zhang Qiao wrote:
> +2.4 RT_RUNTIME_SHARE sched feature
> +----------------------------------
> +
> +RT_RUNTIME_SHARE allows a cpu to borrow rt-runtime from other cpus if it runs
> +out of its own rt-runtime.
> +
> +With this feature enabled, a rt-task may hit 100% cpu usage and can stall other
> +per-cpu tasks like kworkers, as a result, which leads into system hang.
> +
> +Thus, it is advised to disable this feature by default to avoid aforementioned
> +issue unless you know what you're doing.
>  
>  3. Future plans
>  ===============

LGTM, thanks!

Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com>

-- 
An old man doll... just what I always wanted! - Clara

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Re: [PATCH v2] sched/Documentation: Add RT_RUNTIME_SHARE documentation

[Zhang Qiao]

Ping.

在 2024/4/19 17:04, Zhang Qiao 写道:
> RT_RUNTIME_SHARE is an important strategy for rt bandwidth, and
> we should document this sched feature.
> 
> Signed-off-by: Zhang Qiao <zhangqiao22@huawei.com>
> Improvements-suggested-by: Bagas Sanjaya <bagasdotme@gmail.com>
> ---
>  Documentation/scheduler/sched-rt-group.rst | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/Documentation/scheduler/sched-rt-group.rst b/Documentation/scheduler/sched-rt-group.rst
> index d685609ed3d7..eea2fc6f068f 100644
> --- a/Documentation/scheduler/sched-rt-group.rst
> +++ b/Documentation/scheduler/sched-rt-group.rst
> @@ -12,6 +12,7 @@ Real-Time group scheduling
>       2.1 System-wide settings
>       2.2 Default behaviour
>       2.3 Basis for grouping tasks
> +     2.4 RT_RUNTIME_SHARE sched feature
>     3. Future plans
>  
>  
> @@ -146,6 +147,17 @@ 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 to borrow rt-runtime from other cpus if it runs
> +out of its own rt-runtime.
> +
> +With this feature enabled, a rt-task may hit 100% cpu usage and can stall other
> +per-cpu tasks like kworkers, as a result, which leads into system hang.
> +
> +Thus, it is advised to disable this feature by default to avoid aforementioned
> +issue unless you know what you're doing.
>  
>  3. Future plans
>  ===============
>