On Saturday, October 27, 2007 8:01 AM, tesla-dev-bounces at opensolaris.org
wrote:
> 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.
Where do you plan to add a kstat if there is no C-state driver?
> - Currently Solaris only supports C0, C1 states, so this can be
> hard-coded to start.
Sounds fine for now.
> - 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).
Good enough.
> - 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.
Here, on my side, stepping is 4, but supported frequencies have only 3.
4 is read from CPUID, 3 is read from ACPI. And 3 is what we need,
Is it necessary to add a new member of cpu_info?
======================
module: cpu_info instance: 0
name: cpu_info0 class: misc
----snip----
stepping 4
supported_frequencies_Hz 2000000000:2333000000:2667000000
----snip----
======================
> - 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)
Good enough.
> - Can use existing DTrace probes that report on interrupt
> activity (used by intrstat(1m) implementation).
Intrstat just reports device interrupt activity, not enough, I think.
We need to figure out which process is using this device,right?
> - 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).
I'm looking at this now. Is it already done?
> - Battery information
> - Looking to plug into battery related kstats
No machine avaiable for me to test now, :(
>
> I've added the necessary DTrace probes...
You are so quick, after 3 days of SUN Tech days China, the main function
of powertop are almostly ready, ;-).
Did you commit into PowerTop repo?
> 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
>
Good idea, I think linux staff should be willing to accept such an OS
specific layer patch.
Thanks,
-Aubrey
