compiling (large) programs on pbp

[Arwen]

@pine76
Part of the problem is that Pine64 have allowed somewhat aggressive over-clocking of the CPUs. This means that under higher load, the CPU will draw more power than is expected. The only place to get the extra power is the battery. This is perfectly fine for a burst of shorter term activity. For example compiling a small program, or re-calculating a spreadsheet. For other longer running tasks that will drain the battery completely, this over-clocking is bad.

What I think we need, is a software package that:

• Detects external power is plugged in
  
• CPU is busy and has been busy for a while, (like 2nd entry in uptime)
  
• Battery is draining, (meaning it's noticeably dropping charge like 10%)
  

When those conditions are met, throttle the CPUs some. If conditions still exist later, throttle more until the battery is no longer draining.

This will cause the long running task(s), (like the kernel compile), to take longer, but, it will finish. Instead of crashing. The alternative is simply to run those long compiles on another computer.

I have an interest in this as I prefer Gentoo Linux, which compiles most / all the packages from source. This has the advantage of allowing specific options for each package, (for example allowing SCTP for OpenSSH). But, their is zero chance I can perform an update as is, as several hours compiling would likely drain the battery and cause the PBP to crash. So, so for the moment I am using Manjaro and the default Debian.