Re: [PATCH v2] PM / EM: Expose the Energy Model in debugfs

[Greg KH]

On Tue, Jan 22, 2019 at 04:42:47PM +0000, Quentin Perret wrote:
> The recently introduced Energy Model (EM) framework manages power cost
> tables of CPUs. These tables are currently only visible from kernel
> space. However, in order to debug the behaviour of subsystems that use
> the EM (EAS for example), it is often required to know what the power
> costs are from userspace.
> 
> For this reason, introduce under /sys/kernel/debug/energy_model a set of
> directories representing the performance domains of the system. Each
> performance domain contains a set of sub-directories representing the
> different capacity states (cs) and their attributes, as well as a file
> exposing the related CPUs.
> 
> The resulting hierarchy is as follows on Arm juno r0 for example:
> 
>     /sys/kernel/debug/energy_model
>     âââ pd0
>     â âââ cpus
>     â âââ cs:450000
>     â â âââ cost
>     â â âââ frequency
>     â â âââ power
>     â âââ cs:575000
>     â â âââ cost
>     â â âââ frequency
>     â â âââ power
>     â âââ cs:700000
>     â â âââ cost
>     â â âââ frequency
>     â â âââ power
>     â âââ cs:775000
>     â â âââ cost
>     â â âââ frequency
>     â â âââ power
>     â âââ cs:850000
>     â     âââ cost
>     â     âââ frequency
>     â     âââ power
>     âââ pd1
>         âââ cpus
>         âââ cs:1100000
>         â âââ cost
>         â âââ frequency
>         â âââ power
>         âââ cs:450000
>         â âââ cost
>         â âââ frequency
>         â âââ power
>         âââ cs:625000
>         â âââ cost
>         â âââ frequency
>         â âââ power
>         âââ cs:800000
>         â âââ cost
>         â âââ frequency
>         â âââ power
>         âââ cs:950000
>             âââ cost
>             âââ frequency
>             âââ power
> 
> Signed-off-by: Quentin Perret <quentin.perret@xxxxxxx>
> 
> ---
> 
> V2: removed check on return value of debugfs_create_* (Greg KH)
> ---
>  kernel/power/energy_model.c | 57 +++++++++++++++++++++++++++++++++++++
>  1 file changed, 57 insertions(+)

Reviewed-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>