Automated adoption of devkit-power latencies
pknirsch at redhat.com
Tue Nov 11 09:41:36 PST 2008
Richard Hughes wrote:
>>>> I'd personally like to use devkit-power and it's API as a service, as
>>>> overloading it with such functionality might very quickly lead to the
>>>> problems we've seen in the past with HAL where everything was put into
>>>> a single service.
>>> No, I think it's 100% on topic for DK-p. Powersaving is inextricably
>>> linked to latency in my opinion.
>> What about cases where you want to completely shut down a device though
>> as you know it's not used?
> Well, I think for the sort of latencies we are talking about (us and low
> order ms) we need to do this in the kernel driver by default. The logic
> goes like this: If the device isn't being used, power it down _UNLESS_
> it takes more time than $CURRENT_LATENCY_SETTING to wakeup.
> This way everything sleeps by default.
Yep, absolutely agree. But even there wouldn't it be nice if e.g. during
the day that server would have a 10us latency for CPU and during the
night automatically transition to higher and higher latencies, up to
even 100ms or so? Or a desktop system that has a screenlock running
overnight, the user forgot to close his firefox window with a flash
plugin running in it. Thats what i'm thinking about at least. Not to
have a fixed latency but a dynamic one that, depending on whats going on
on the system adapts those.
And devices that take a lot longer to power down resp. up e.g. harddisks
aren't addresses by the latency changes yet if i remember correctly?
Philipp Knirsch | Tel.: +49-711-96437-470
Team Lead Core Services | Fax.: +49-711-96437-111
Red Hat GmbH | Email: Phil Knirsch <pknirsch at redhat.com>
Hauptstaetterstr. 58 | Web: http://www.redhat.com/
D-70178 Stuttgart, Germany
Motd: You're only jealous cos the little penguins are talking to me.
More information about the devkit-devel