lkml.org 
[lkml]   [2022]   [Mar]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[[PATCH 6/8] Documentation: EM: Add artificial EM registration description
    Date
    Add description about new artificial EM registration and use cases.
    Update also the documentation with the new .get_cost() callback
    description and usage.

    Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
    ---
    Documentation/power/energy-model.rst | 20 ++++++++++++++++++++
    1 file changed, 20 insertions(+)

    diff --git a/Documentation/power/energy-model.rst b/Documentation/power/energy-model.rst
    index fd29ed2506c0..feb257b7f350 100644
    --- a/Documentation/power/energy-model.rst
    +++ b/Documentation/power/energy-model.rst
    @@ -123,6 +123,26 @@ allows a platform to register EM power values which are reflecting total power
    (static + dynamic). These power values might be coming directly from
    experiments and measurements.

    +Registration of 'artificial' EM
    +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    +
    +There is an option to provide a custom callback for drivers missing detailed
    +knowledge about power value for each performance state. The callback
    +.get_cost() is optional and provides the 'cost' values used by the EAS.
    +This is useful for platforms that only provide information on relative
    +efficiency between CPU types, where one could use the information to
    +create an abstract power model. But even an abstract power model can
    +sometimes be hard to fit in, given the input power value size restrictions.
    +The .get_cost() allows to provide the 'cost' values which reflect the
    +efficiency of the CPUs. This would allow to provide EAS information which
    +has different relation than what would be forced by the EM internal
    +formulas calculating 'cost' values. To register an EM for such platform, the
    +driver must set the flag 'milliwatts' to 0, provide .get_power() callback
    +and provide .get_cost() callback. The EM framework would handle such platform
    +properly during registration. A flag EM_PERF_DOMAIN_ARTIFICIAL is set for such
    +platform. Special care should be taken by other frameworks which are using EM
    +to test and treat this flag properly.
    +
    Registration of 'simple' EM
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~

    --
    2.17.1
    \
     
     \ /
      Last update: 2022-03-17 00:53    [W:3.246 / U:0.152 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site