OpenSolaris power management

One aspect of OpenSolaris that I've taken an interest in is power management. In my research, I've come across several useful things.

One of the first things I tried to find was the current CPU speed to see if power management was doing anything. I finally stumbled across this post by Mark Haywood. In that post he shows these commands:

$ kstat -m cpu_info -s supported_frequencies_Hz
module: cpu_info                        instance: 0
name:   cpu_info0                       class:    misc
       supported_frequencies_Hz        2800000000:3200000000

$ kstat -m cpu_info -s current_clock_Hz
module: cpu_info                        instance: 0
name:   cpu_info0                       class:    misc
       current_clock_Hz                2800000000

These report the supported frequencies and the current frequency of the CPU. If the supported frequencies field shows a range as indicated above, OpenSolaris supports power management for your CPU.

Another very handy tool is PowerTop. It captures statistics about how much CPU time is idle, how much time it spends running at different speeds, and what is causing the CPU to wake up from idle most frequently.