Definition of "balanced"
At least currently, it appears to me that the default as the daemon starts up will be "balanced" regardless of the actual state of the system. That means that knobs can be tweaked, the daemon restarted and it thinks that it's in a balanced state again.
I think it's very important that the actual power state be pre-defined, set and measured by a daemon like this. Here's my reasoning:
- Due to historical reasoning, some kernel drivers will not turn on runtime power management by default
- Default kernel policy can be configured to have NVME and ATA disks behave differently as a compile time decision.
- Software like TLPand tuned will potentially adjust the same knobs, and cause at worst conflicts, and at best expectation mismatches.
So I would propose that as part of daemon startup the balanced profile actually get the system into a "balanced" state. The list of knobs that are tweaked should be available as an XML file or something similar.
As a comparison to the similar power slider implemented Windows 10 this to me would mean something that barring kernel bugs passes common energy compliance criteria such as Energy Star 8. If done properly, I would expect the need for something like TLP or tuned to get good out of the box energy consumption to go away.