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

[Rafael J. Wysocki]

On Wednesday, January 23, 2019 10:28:36 AM CET Quentin Perret wrote:
> On Tuesday 22 Jan 2019 at 19:41:36 (+0100), Greg KH wrote:
> > 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>

Applied, thanks!