| Message ID | 20220321095729.20655-7-lukasz.luba@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Introduce support for artificial Energy Model | expand |
Thanks for documenting this as well. On Monday 21 Mar 2022 at 09:57:27 (+0000), Lukasz Luba wrote: > 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 Maybe it worth adding a note here that the power values provided with .get_power() are only for information purposes and that they don't have any functional use. > +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 > ~~~~~~~~~~~~~~~~~~~~~~~~~~~ > Reviewed-by: Ionela Voinescu <ionela.voinescu@arm.com> > -- > 2.17.1 >
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 ~~~~~~~~~~~~~~~~~~~~~~~~~~~
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(+)