Those are interest questions. Let me investigate about them and as soon as I get some useful information I will post it here.
I also am very interested in this question. The default energy consumption of the Atom CPU on the Edison is pretty high and I wan't to see if I can better manage the battery life.
I did some more digging into this today to see if the Edison would respond to any typical ways of changing the CPU into different power states. Nothing I tried seemed to have much impact yet though I have concluded testing. I'll post some rough notes of what I tried for build on or share their experiences. That being said I guess none of us will get too far until we have more info from Intel that I gather they are collecting now given Diego's statement above.
So I noted when exploring the /sys/device/* file system that each core of the Atom are shown as cpu0 and cpu1 (e.g., /sys/devices/system/cpu/cpu0/). When I explored in both cores the available frequencies it seems that only 1 is possible -- 500 Mhz, such as when I tried this:
root@edison:/sys/devices/system/cpu/cpu0/cpufreq# cat scaling_available_frequencies
There were three governors available:
root@edison:/sys/devices/system/cpu/cpu0/cpufreq# cat scaling_available_governors
ondemand userspace performance
But when I tried these settings I didn't find much performance or energy difference -- though I just had a quick look.
Under each core I found 4 states available (/sys/devices/system/cpu/cpu0/cpuidle/stateX) Typical values for these states were as so:
/sys/devices/system/cpu/cpu0/cpuidle/state0/desc:CPUIDLE CORE POLL IDLE
And each has a description that seemed meaningful, though I didn't know how to interpret it. I tried disabling each state while under different governor settings thinking that this might change which power states were available during computation but again this didn't seem to result in much change.
I saw there were options for potentially turning off cores as is possible in other platforms for example:
root@edison:/sys/devices/system/cpu# echo 1 > /sys/devices/system/cpu/offline
-sh: can't create /sys/devices/system/cpu/offline: Permission denied
But as you can see the OS complained. Anyway I hope this helps others who are searching for the same type of options. And perhaps someone can suggest other things to try.
I just wanted to ask for a status update about power saving.
There is no update yet. We are still investigating about the C-states. When I get information about it I will post it here.
Any updates? This is 3 months later..
6 months later....please give some support for this mandatory feature.
I wonder if anyone found something useful about this topic?
I would also appreciate some update on the status of power saving in Edison.
Pretty please tell me that you finished investigating months ago but just forgot to tell me!
I know a lot of time has passed, and you have been waiting for an update on this topic. We've been investigating on this, but unfortunately, this functionality is not implemented even in the new releases, and currently there are no plans to implement power management.