Hi, On 12/2/20 6:11 PM, Mark Pearson wrote: > On modern systems the platform performance, temperature, fan and other > hardware related characteristics are often dynamically configurable. The > profile is often automatically adjusted to the load by some > automatic-mechanism (which may very well live outside the kernel). > > These auto platform-adjustment mechanisms often can be configured with > one of several 'platform-profiles', with either a bias towards low-power > consumption or towards performance (and higher power consumption and > thermals). > > Introduce a new platform_profile sysfs API which offers a generic API for > selecting the performance-profile of these automatic-mechanisms. > > Co-developed-by: Mark Pearson <markpearson@xxxxxxxxxx> > Signed-off-by: Mark Pearson <markpearson@xxxxxxxxxx> > Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx> Thank you, patches 1 and 2 look good to me now, you may add my: Reviewed-by: Hans de Goede <hdegoede@xxxxxxxxxx> To patch 2 (since I'm co-author of patch 1 it would be a bit weird to add it there too). Rafael, it would be great if you pick up patches 1 and 2 for merging into 5.11 (assuming that you agree that they are ready) then I will merge patch 3 once 5.11-rc1 is out. Regards, Hans > --- > Changes in v2: > - updated to rst format > Changes in v3, v4 & v5: > - version bump along with rest of patch series > > .../ABI/testing/sysfs-platform_profile.rst | 66 +++++++++++++++++++ > 1 file changed, 66 insertions(+) > create mode 100644 Documentation/ABI/testing/sysfs-platform_profile.rst > > diff --git a/Documentation/ABI/testing/sysfs-platform_profile.rst b/Documentation/ABI/testing/sysfs-platform_profile.rst > new file mode 100644 > index 000000000000..5f7b2a94409b > --- /dev/null > +++ b/Documentation/ABI/testing/sysfs-platform_profile.rst > @@ -0,0 +1,66 @@ > +======================================================================= > + Platform Profile Selection (e.g. /sys/firmware/acpi/platform_profile) > +======================================================================= > + > + > +On modern systems the platform performance, temperature, fan and other > +hardware related characteristics are often dynamically configurable. The > +profile is often automatically adjusted to the load by some > +automatic mechanism (which may very well live outside the kernel). > + > +These auto platform adjustment mechanisms often can be configured with > +one of several platform profiles, with either a bias towards low power > +operation or towards performance. > + > +The purpose of the platform_profile attribute is to offer a generic sysfs > +API for selecting the platform profile of these automatic mechanisms. > + > +Note that this API is only for selecting the platform profile, it is > +NOT a goal of this API to allow monitoring the resulting performance > +characteristics. Monitoring performance is best done with device/vendor > +specific tools such as e.g. turbostat. > + > +Specifically when selecting a high performance profile the actual achieved > +performance may be limited by various factors such as: the heat generated > +by other components, room temperature, free air flow at the bottom of a > +laptop, etc. It is explicitly NOT a goal of this API to let userspace know > +about any sub-optimal conditions which are impeding reaching the requested > +performance level. > + > +Since numbers on their own cannot represent the multiple variables that a > +profile will adjust (power consumption, heat generation, etc) this API > +uses strings to describe the various profiles. To make sure that userspace > +gets a consistent experience this API document defines a fixed set of > +profile names. Drivers *must* map their internal profile representation > +onto this fixed set. > + > + > +If there is no good match when mapping then a new profile name may be > +added. Drivers which wish to introduce new profile names must: > + > + 1. Explain why the existing profile names canot be used. > + 2. Add the new profile name, along with a clear description of the > + expected behaviour, to the documentation. > + > +:What: /sys/firmware/acpi/platform_profile_choices > +:Date: October 2020 > +:Contact: Hans de Goede <hdegoede@xxxxxxxxxx> > +:Description: This file contains a space-separated list of profiles supported for this device. > + > + Drivers must use the following standard profile-names:: > + > + low-power: Low power consumption > + cool: Cooler operation > + quiet: Quieter operation > + balanced: Balance between low power consumption and performance > + performance: High performance operation > + > + Userspace may expect drivers to offer more than one of these > + standard profile names. > + > +:What: /sys/firmware/acpi/platform_profile > +:Date: October 2020 > +:Contact: Hans de Goede <hdegoede@xxxxxxxxxx> > +:Description: Reading this file gives the current selected profile for this > + device. Writing this file with one of the strings from > + available_profiles changes the profile to the new value. >
