diff mbox series

sched/Documentation: Add RT_RUNTIME_SHARE documentation

Message ID 20240131123238.2332064-1-zhangqiao22@huawei.com
State New
Headers
Series sched/Documentation: Add RT_RUNTIME_SHARE documentation |

Commit Message

Zhang Qiao Jan. 31, 2024, 12:32 p.m. UTC 
  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>
---
 Documentation/scheduler/sched-rt-group.rst | 11 +++++++++++
 1 file changed, 11 insertions(+)

Comments

Jonathan Corbet Feb. 28, 2024, 10:44 p.m. UTC | #1 
Zhang Qiao <zhangqiao22@huawei.com> writes:

> 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>
> ---
>  Documentation/scheduler/sched-rt-group.rst | 11 +++++++++++
>  1 file changed, 11 insertions(+)
>
> diff --git a/Documentation/scheduler/sched-rt-group.rst b/Documentation/scheduler/sched-rt-group.rst
> index d685609ed3d7..4d8eceb71f5e 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 +147,16 @@ 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.
> +
> +With this feature enabled, a rt-task probably hits 100% cpu usage and starves
> +per-cpu tasks like kworkers, as a result, it may hang up the whole system.
> +Therefore, in order to avoid such exception, recommand to disable this feature
> +by default unless you really know what you're up to.

So this doesn't appear to have been picked up by anybody...should I
carry it in docs, or is there some other reason why it hasn't gone in?

Thanks,

jon
diff mbox series

Patch

diff --git a/Documentation/scheduler/sched-rt-group.rst b/Documentation/scheduler/sched-rt-group.rst
index d685609ed3d7..4d8eceb71f5e 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 +147,16 @@  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.
+
+With this feature enabled, a rt-task probably hits 100% cpu usage and starves
+per-cpu tasks like kworkers, as a result, it may hang up the whole system.
+Therefore, in order to avoid such exception, recommand to disable this feature
+by default unless you really know what you're up to.
 
 3. Future plans
 ===============