https://fedoraproject.org/wiki/Changes/ThermalManagementWS

== Summary ==
Better thermal management and peak performance on Intel CPUs by including thermald in the default install.

== Owner ==
* Name: [[User:benzea| Benjamin Berg]]
* Email: bberg@redhat.com

* Name: [[User:ckellner| Christian J. Kellner]]
* Email: ckellner@redhat.com

* Product: Workstation
* Responsible WG: Workstation


== Detailed Description ==

Modern Intel-based systems provide sensors and methods to monitor and control temperature of its CPUs. The Thermal daemon will use those sensors to monitor the temperature and use the best available method to keep the CPU in the right temperature envelop. On certain systems this is needed to reach the maximal performance. thermald will for example use the PPCC power table to set power limits (when available, see for example https://www.mail-archive.com/kernel-packages@lists.launchpad.net/msg411614.html). This is for example the case on Ice Lake, where thermald can increase the performance of the out-of-the-box behaviour of Fedora.

Not strictly necessary, but *further* improvements can be achieved by using per-model thermald configurations. The most straight forward way of using those is for the user to install dptfxtract (available from rpmfusion). At least parts of what dptfxtract can already do may be integrated into thermald in the future thanks to the reverse engineering work done by Matthew Garret (see https://github.com/intel/thermal_daemon/tree/mg_patches_test, https://github.com/intel/thermal_daemon/pull/224). Should the reverse engineering effort be merged, or if the user installs dptfxtract, then they can expect a performance boost on some machines.

Theoretically one could ship appropriate per-machine configurations as a separate package (or inside thermald). However, this is not part of the proposal for a number of reasons:
 1. It is not clear how the configuration data can be collected
 2. We do not currently have an implementation to load such configuration data
 3. This may become obsolete with if the reverse-engineering effort continues and is merged (or picked up by Fedora)

For a more details explanation please consult Intel's [https://01.org/linux-thermal-daemon/documentation/introduction-thermal-daemon introduction] to thermald.

== Benefit to Fedora ==
Better out-of-the-box experience due to improved cooling methods and performance on Intel systems. This affects many modern laptops (e.g. the Ice Lake platform). On affected machines, Fedora would continue to have poorer performance compared to other distributions.

== Scope ==
* Proposal owners:
 - Include the thermald package in the default Workstation install

* Other developers: N/A (not a System Wide Change)
* Release engineering:
* Policies and guidelines: N/A (not a System Wide Change)
* Trademark approval: N/A (not needed for this Change)

== Upgrade/compatibility impact ==
N/A (not a System Wide Change)

== How To Test ==

Install the packages and use e.g. turbostat to monitor the performance. Improvements may only be visible if the non-free dptfxtract package is also installed.

== User Experience ==
 - Better performance on certain hardware
 - Better cooling of CPUs on certain hardware

== Dependencies ==
N/A (not a System Wide Change)

== Contingency Plan ==
* Contingency mechanism: Don't ship package by default
* Contingency deadline: N/A (not a System Wide Change) 
* Blocks release? N/A


--
Ben Cotton
He / Him / His
Senior Program Manager, Fedora & CentOS Stream
Red Hat
TZ=America/Indiana/Indianapolis