The existing powertop implementation makes heavy use of /proc under Linux.
For the necessary interfaces, here's what I'm thinking:
- C-state information
- Number of C-states, and amount of time system is spending in
each one
- Number of C-states can eventually be exported through a kstat.
- Currently Solaris only supports C0, C1 states, so this can be
hard-coded to start.
- Amount of time spent in each C-state can be measured by a
DTrace probe which fires
during C-state transistions (around mwait, halt instruction
invocations).
- P-state information
- Number of P-states, their frequencies, and amount of time
system is spending in each one.
- Number of P-states, frequencies, and current state already
exported through cpu_info kstats.
- Amount of time spent in each P-state can be meausured by a
DTrace probe which fires
when system changes CPU speed.
- Event information (interrupts)
- Can use existing DTrace probes that report on interrupt
activity (used by intrstat(1m) implementation).
- Event information (timer / callout activity)
- Can use existing callout related DTrace probes to report on
who's waking up and why (kernel and user activity).
- Battery information
- Looking to plug into battery related kstats
I've added the necessary DTrace probes...so i'm going to work on
extracting and formatting the needed data from the kernel
via libdtrace, and libkstat. I've taken a pass through powertop.c and
prepped the code for the Solaris changes (removing the Linux
specific portions). Once we get this prototyped, we should look at how
all this can be done so that we have the Linux and Solaris
specific code exists in an OS specific layer, with the common code being
common to both. That way, all this can live in a common
source base.
-Eric
