Re: [dpdk-dev] [PATCH v2 3/3] doc: update vm_power_manager cmdline options in doc

["Hunt, David" <david.hunt@intel.com>]

On 18/5/2020 11:39 AM, Sexton, Rory wrote:
> Signed-off-by: Rory Sexton <rory.sexton@intel.com>
> ---
>   doc/guides/sample_app_ug/vm_power_management.rst | 13 +++++--------
>   1 file changed, 5 insertions(+), 8 deletions(-)
>
> diff --git a/doc/guides/sample_app_ug/vm_power_management.rst b/doc/guides/sample_app_ug/vm_power_management.rst
> index e98277ccb..dd0f46158 100644
> --- a/doc/guides/sample_app_ug/vm_power_management.rst
> +++ b/doc/guides/sample_app_ug/vm_power_management.rst
> @@ -410,20 +410,17 @@ There are a couple of command line parameters for enabling the out-of-band
>   monitoring of branch ratios on cores doing busy polling using PMDs as
>   described below:
>   
> -``--core-list {list of cores}``
> +``--core-branch-ratio {list of cores}:{branch ratio for listed cores}``
>      Specify the list of cores to monitor the ratio of branch misses
>      to branch hits.  A tightly-polling PMD thread has a very low
>      branch ratio, therefore the core frequency scales down to the
>      minimum allowed value. On receiving packets, the code path changes,
>      causing the branch ratio to increase. When the ratio goes above
>      the ratio threshold, the core frequency scales up to the maximum
> -   allowed value.
> -
> -``--branch-ratio {ratio}``
> -   Specify a floating-point number that identifies the threshold at which
> -   to scale up or down for the given workload. The default branch ratio
> -   is 0.01 and needs adjustment for different workloads.
> -
> +   allowed value. The specified branch-ratio is a floating point number
> +   that identifies the threshold at which to scale up or down for the
> +   elements of the core-list. If not included the default branch ratio of
> +   0.01 but will need adjustment for different workloads

Could I suggest adding something along the following lines for further info?

"This parameter can be used multiple times for different sets of cores.
The branch ratio mechanism can also be useful for non-PMD cores and 
hyper-threaded
environments where C-States are disabled."


Reviewed-by: David Hunt <david.hunt@intel.com>