[systemd-devel] systemd and power management

[Daniel Hollocher]

Yeah, it's tricky.

I don't think sysctl is the answer as that doesn't work with /sys

On Wed, Oct 29, 2014 at 1:06 PM, Ivan Shapovalov <intelfx100 at gmail.com>
wrote:

> On Wednesday 29 October 2014 at 13:00:42, Daniel Hollocher wrote:
> > Hey folks,
> > I'm a not expert here, so please forgive the low quality/interest of my
> > question.
> >
> > I'm curious what the ideal systemd way is to set various power management
> > settings in the /sys tree.  For me personally, I'm looking to set
> > sampling_down_factor as without it, ondemand has terrible performance on
> my
> > particular computer (a 10-30% loss compared to performance or
> conservative).
> >
> > Currently, Ubuntu uses a sysv init script to set ondemand after boot,
> and I
> > could edit that.  It would be cool to know the ideal systemd way, that
> > could also be aware of power saving stuff.
> >
> > From googling, it seems that tempfiles or sysctrl is not the way to go,
> > since those only happen at boot.  Udev?  The examples I've found seem to
> > make basic usage of udev to detect power changes, and then drop to a
> script
> > to do the bulk of the work.  Is that it?
>
> You could write a bunch of units pulled in by a target... well, two
> targets,
> one for power-saving and second for performance mode. And then just start
> the
> targets from an udev rule. Just remember to use `--no-block` as udev kills
> workers after some time.
>
> I've already done something along these lines for my own purposes, see
> https://github.com/intelfx/power-management
>
> However, I still want to know if I this is OK wrt systemd "spirit".
>
> --
> Ivan Shapovalov / intelfx /
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