NetBSD powerd wish-list item, 2009-03-14 00:00:00 #
We had an interesting discussion on EFNet/#netbsd this morning about some possible enhancements to acpi and some other facilities being improved/introduced in NetBSD 5. The main idea was this: given a set of criteria, could netbsd automatically turn off hardware components to save on power? So, for a simple example, if I have a server with two cpu's and my system load is less than 1 for an extended period of time, why not step down my cpu speed and if my load continues to stay low, turn off one cpu? What if I never use more than half of my ram? Or what if my network traffic could go from gig to 100M without any harm? I've worked in some power and cooling-starved datacenters where we would never seriously consider trying to set all of this stuff up, while at the same time we had a lot of standby servers, or very idle systems. This tells me that power management is probably seen as risky, difficult, or both. All of this stuff, of course, also applies to laptops which need extended battery performance, lid-closing sleeps, etc. It's one of the few places where laptop-driven technology could make a big impact in a datacenter. Anyway, netbsd isn't really there yet to provide a lot of this, but it seems to have facilities which could be put together to almost solve the problem: And maybe something more like sar or a similar dtrace-type listener.