The Increasing Importance Of ACPI Platform Profiles With Today's Throttle-Happy Hardware

As covered several times going back to the end of last year, ACPI Platform Profile support has materialized in recent versions of the Linux kernel for the core infrastructure and implementations that work with the latest laptops from the likes of Dell, Lenovo, ASUS, and HP. This platform profile support is becoming increasingly important with expressing your power/cooling/performance preference so that your laptop behaves as one would expect.

While it would be nice to have a modern, slim notebook that can run at full-speed without throttling so quickly, that unfortunately is increasingly rare with today's processors and vendors going for increasingly thin designs that means compromising thermals. Plus with today's increasingly complicated processors and Intel SoCs requiring Thermald and now with ACPI platform profiles becoming necessary, it has rather complicated the Linux support.

Longtime Linux kernel developer and block subsystem maintainer, Jens Axboe recently conveyed his frustrations with "stupid throttling" where his new Lenovo X1 Carbon Gen9 laptop is "unusable in certain scenarios" like compiling the Linux kernel while running on AC as it ends up throttling all the way down to 400MHz...

Anyone have a gen 9 Lenovo X1 Carbon and seeing stupid throttling? Almost makes it unusable in certain scenarios. If plugged in to AC and you run a make -j4 kernel compile, it often throttles to 400MHz. Useless...

— Jens Axboe (@axboe) September 16, 2021

If you find yourself in a similar situation with very poor out-of-the-box/default laptop performance, it turned out at least with this recent Lenovo laptop the "performance" ACPI platform profile needs to be explicitly used to avoid this otherwise horrible performance.

This was the solution to my X1 insane throttling issue. Sharing in case anyone else has this problem, because it practically renders the laptop useless... https://t.co/Sa0nca6R6p

— Jens Axboe (@axboe) September 17, 2021

Setting the platform profile preference can be done from the command-line via the /sys/firmware/acpi/platform_profile sysfs interface while forthcoming desktop updates from the likes of GNOME and KDE are also adding UI controls for more easily setting the ACPI Platform Profile.