Request for feedback and/or participation on https://fedoraproject.org/wiki/Features/PowerManagement

[Peter Robinson]

> Of course most of the first points are things that the user just needs to do
> himself (power off his machine, choose the right dimension for the work he's
> doing etc).
>
> From the pure system ones i know that we at least already use the ondemand
> by default as soon as the CPU supports it, so we should be fine there.
>
> Network card speeds and harddisk spindowns is a bit tricker imo, though we
> probably could enable a higher powersave mode for harddisk by default at
> least in case a user wants to save power. Some of this is/will be addressed
> by the tuned i'm working on which monitors the usage of network and harddisk
> devices and dynamically adapts the settings to the current use.

It also depends on the actual switch settings as well. If the
switchport is pegged at 100/Full there's no way we can change the NIC
settings because we then lose network altogether. In a server
environment this is common for various reasons (I work in for a
enterprise hosting company with tens of thousands of switch ports,
probably 80-90% are pegged at a specific setting).

> Laptop mode and a higher value for dirty_writeback_centisecs, there i'm
> personally torn a bit myself. I personally do use it on all my machines
> (laptop and desktop), but i can understand people who are a bit paranoid
> about their data integrity not wanting to have that by default. But i'd
> personally be all for going that way.

Also there are settings I believe that are much more optimal for SSDs
so there should probably be something that allows for that as well and
that detects Disk vs SSD.

> In regard to relatime from what i've found so far we seem to be doing that
> already by default it seems, though i'd like to have that verified.
>
> Then disabling CD-ROM polling is definitely something for the ServerSIG, but
> on a default Desktop i think the user experience would suffer if we would do
> that by default.

I was under the impression that the reason HAL polls for CD drives is
for old and/or buggy CD drives that don't support the media change
functionality or at least something to that effect. Is that still an
issue with older drives? Also there's a bug where HAL still polls when
there's no CD drive. See RHBZ 464104 it polls the SD card in my eeePC
901.

> Enabling USB autosuspend looks like a good candidate for being a default
> though. I've used it on quite a few Fedora 10 machines around here and
> haven't experienced any problems so far, so it seems to have matured enough
> by now from what i can see.

How do you enable that in Fedora 10?

> Last but not least the dpms off, i think that should definitely be part of
> the Desktop screensaver defaults, especially if you look at how much power a
> modern LCD display eats when it's only dimmed down to black.

And for server too? If there's no screen attached to a VGA port does
dpms off still save power on a video chipset by turning off stuff?
Also I've seen some discussion on turning off one screen when its not
in use (like watching a video on one screen and turning off the other
in a dual screen env).

Peter