Talk
Power Management on Linux: From the Hardware to the Kernel and User Space Interfaces
Sergio Prado
49:53
Power management on modern hardware is quite complex. There are so many concepts and features provided by the hardware like frequency scaling, idle states, wake-up sources, sleep states, suspend-to-RAM, hibernation, etc! All this needs to be abstracted so kernel and user space code can properly manage power consumption.
In this talk, we will deep dive into all these concepts, from the resources provided by the hardware to standard and portable software interfaces provided by the kernel and consumed by device drivers and user space applications, including tools and techniques to monitor and improve power consumption on an embedded Linux system.
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According to Sergio Prado, why is hardware design important for power management on Linux systems?
A
Because if the hardware lacks power-management features, software will struggle to manage power.
B
Because software can always compensate for any missing hardware features by implementing special drivers.
C
Because only the CPU architecture (ARM vs x86) determines all power behavior; other hardware choices don't matter.
D
Because power management is handled entirely by firmware such as UEFI/BIOS, not by the kernel.
E
Because adding extra resistors on the board always improves power consumption.
Really great presentation! The last line of the summary is really worth emphasizing:
"Power management is a system-wide challenge and requires a holistic approach!"
It certainly does! As well as the software, there needs to be hardware support for example to switch external regulators or devices and clocks off to reduce consumption, and the product may need heat dissipation strategies to avoid the kernel thermal management acting to throttle CPU and GPU and thus render the user experience unacceptable. It can be a very painful lesson to learn.