Comments on: DeviceKit-power latency control

By: hughsie

hughsie — Mon, 01 Dec 2008 10:46:29 +0000

@Tore:

Sure, not everything is latency related, some will be user preferences once again. I don’t want DeviceKit-power to be a policy agent like PPM or OHM, that is better left to the session in the laptop / desktop use case.

By: Tore

Tore — Sat, 29 Nov 2008 16:33:43 +0000

Not everything you’ll want to do in order to conserve power when on battery has to do with latency. For example:

- shutting down unused radios such as bluetooth or wlan
- lowering display panel brightness
- shortening time required for display panel to shut down
- enabling automatic suspend-to-ram when inactive
- avoiding running non-essential background tasks such as updatedb

Do you plan for your system service to handle such things, or should that be left to something else, like for instance PPM?

By: hughsie

hughsie — Fri, 07 Nov 2008 12:55:25 +0000

@Frederik:

No, the daemon is system activated, so if you’re not using it, it never gets launched.

By: hughsie

hughsie — Fri, 07 Nov 2008 12:52:10 +0000

@Priit:

I don’t think it’s over engineering, I think it’s required for todays latency critical server workload, and the modern desktop. You don’t need to do it, but if you don’t have something like this you can’t turn on powersaving modes by default without the system running like molasses.

By: Frederik

Frederik — Fri, 07 Nov 2008 12:49:47 +0000

I’m not sure how this is all supposed to work. I hope this is not yet another daemon to run? I read on Planet GNOME work is being done to improve GNOME’s start up time. Then it would be a shame that new bloat is added again. That would be two steps forward and one backward.

By: Priit Laes

Priit Laes — Thu, 06 Nov 2008 18:37:29 +0000

Hum.. I see that a bunch of use cases are about running some kind of server (sql server, cron scripts). Isn’t power latency control a bit overengineering in these cases, as how many serious admins are running desktop environment on a business-critical server machine?

By: davidz

davidz — Thu, 06 Nov 2008 14:56:28 +0000

Uhm, not sure we should be using your blog as a mailing list – any chance you can post this to devkit-devel; I have a few comments. Thanks!

http://lists.freedesktop.org/mailman/listinfo/devkit-devel

By: onox

onox — Thu, 06 Nov 2008 12:46:40 +0000

if I understand it correctly: the latency control thing is used to give the kernel some information about how much time it can let devices sleep? What’s the difference with a system that not this latency control thing?

By: Johannes Berg

Johannes Berg — Thu, 06 Nov 2008 11:51:43 +0000

@hughsie:

First, apologies for missing that h!

Can’t say I’m offended, in particular not by you (!), I’m just somewhat disappointed that we discussed the wireless power management aspect at OLS and nobody there was aware of pm-qos, not even the Intel folks who work on wireless. It seems like at least some of the pm-qos design was done without asking the users, which isn’t always the best idea…

By: hughsie

hughsie — Thu, 06 Nov 2008 11:35:59 +0000

@Johannes:

Perhaps. Not sure, as I don’t get that involved, sorry. I assumed it was upstream — if you watch the video the details were presented (with code…) so I assumed it was committed. Apologies if this is not true, and I caused offence.