[CentOS] CentOS 7 speedstep CPU support

Fri May 12 13:09:58 UTC 2017
ken <gebser at mousecar.com>

On 05/11/2017 08:41 PM, Kahlil Hodgson wrote:
> On Fri, May 12, 2017 at 8:18 AM, ken <gebser at mousecar.com> wrote:
>> Currently I don't actually need more speed.  This is already a fairly peppy
>> laptop... like right now the load is about 2%.  If it was any lower, I could
>> almost turn this machine  off and still run everything.  :)  Ah but
>> seriously, I'd rather have the speed cranked down and save the battery.
>> That's the one weak spot: this gal can drain a battery faster than a dog can
>> down a bag of cookies.  Still, I'd like to have control in gnome over cpu
>> speed again.
> I think all that stuff is controlled by 'tuned' now. There is gtk app
> tuned-gtk to help setting and switching profiles.

Hey, so it is.  Thanks, Kahil.  I don't think I ever would have found 
that on my own.

According to the Description in the RPM though, "Currently only ethernet 
network and ATA harddisk devices are implemented."  That statement might 
be out of date, for in /var/log/tuned/tuned.log there is output implying 
control of the CPU (e.g., "INFO tuned.plugins.plugin_cpu: setting 
energy_perf_bias 'normal' on cpu 'cpu7'").  However, there are also 
numerous ERROR statements following those INFOs, e.g., "ERROR    
tuned.utils.commands: Executing x86_energy_perf_policy error: pwrite: 
Operation not permitted" and "ERROR    tuned.utils.commands: Reading 
/sys/class/drm/card0/device/power_method error: [Errno 2] No such file 
or directory: u'/sys/class/drm/card0/device/power_method'".

It looks like that needs a bit more development.  But at least now I 
know what to keep an eye to.

Thanks again.