[Pommed-devel] pommed and powertop

[Julien BLACHE]

Arthur Amarra <arthur_amarra at yahoo.co.uk> wrote:

Hi,

> pommed and gpommed works wonderfully, thank you so much for developing
> this app.

You're welcome :)

> This is more of a feature request than anything, but when I am running
> Powertop (www.linuxpowertop.org) , I notice that gpommed and pommed
> are responsible for around 15-20 and 5 CPU wakeups per second
> respectively.

OK, so, in a nutshell:
 - pommed will wake up 5 times per second no matter what you do, and
   you really can't help that (under 200ms pommed isn't reactive
   enough).
 - pommed will also wake up everytime you press a key on the keyboard,
   don't forget that when running powertop...

 - gpomme can probably be tweaked to wake up less often than it
   currently does; I do not have the time to look into that, so
   anybody that can come up with a decent patch for that is welcome to
   send it my way :)

> Now I know that polling is one of the most effective and efficient
> ways to monitor the status of the backlight, etc. but using a
> notification system like inotify would save some of these wakeups from
> happening and increase the battery life.

inotify for the ambient light sensors isn't a good idea at all. The
values differ pretty much every time you have a look at
them. Moreover, the ambient light sensors on the MacBook are polled
on-demand by the applesmc driver. Issueing more requests to the SMC
will only create more problems at this level (keeping the SMC busy
etc).

(IIRC applesmc doesn't support poll() anyway)

And please everybody realize that the extremely low numbers the Intel
folks are pushing are nothing more than marketing. There's no way to
reach these numbers on any kind of real world setup.

They're trying to make up for their complete inability to produce
decent hardware that doesn't require a portable nuclear power plant to
run longer than one hour.

JB.

-- 
Julien BLACHE                                   <http://www.jblache.org> 
<jb at jblache.org>                                  GPG KeyID 0xF5D65169