Re: [PATCH v7 01/12] Documentation: x86: Add AMD Hardware Feedback Interface documentation

[Peter Zijlstra]

On Sat, Nov 30, 2024 at 08:06:52AM -0600, Mario Limonciello wrote:

> +Thread Classification and Ranking Table Interaction
> +----------------------------------------------------
> +
> +The thread classification is used to select into a ranking table that describes
> +an efficiency and performance ranking for each classification.
> +
> +Threads are classified during runtime into enumerated classes. The classes represent
> +thread performance/power characteristics that may benefit from special scheduling behaviors.
> +The below table depicts an example of thread classification and a preference where a given thread
> +should be scheduled based on its thread class. The real time thread classification is consumed
> +by the operating system and is used to inform the scheduler of where the thread should be placed.
> +
> +Thread Classification Example Table
> +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> ++----------+----------------+-------------------------------+---------------------+---------+
> +| class ID | Classification | Preferred scheduling behavior | Preemption priority | Counter |
> ++----------+----------------+-------------------------------+---------------------+---------+
> +| 0        | Default        | Performant                    | Highest             |         |
> ++----------+----------------+-------------------------------+---------------------+---------+
> +| 1        | Non-scalable   | Efficient                     | Lowest              | PMCx1A1 |
> ++----------+----------------+-------------------------------+---------------------+---------+
> +| 2        | I/O bound      | Efficient                     | Lowest              | PMCx044 |
> ++----------+----------------+-------------------------------+---------------------+---------+
> +
> +Thread classification is performed by the hardware each time that the thread is switched out.
> +Threads that don't meet any hardware specified criteria will be classified as "default".

I'm not seeing this part in the patches, am I needing to read more
careful?