Power consumption out of box

Alan Pope alan at popey.com
Mon Oct 15 09:38:21 BST 2007

Hi Justin,

On Sun, 2007-10-14 at 17:51 -0500, Justin Dugger wrote:
> Phoronix had an article recently on measuring Ubuntu power
> consumption.  It's general conclusion is that 2007 has been a bad year
> for battery lifetime, with feisty and gutsy both having large jumps in
> power consumption out of box.  You can find the article at
> http://www.phoronix.com/scan.php?page=article&item=878

It's an interesting article. I'd like to see the same test done on other
hardware. I have a nice range of 4 laptops here which could be used for
such a test if there was a plan to do this.

> * Have you noticed a similiar pattern to Phoronix's results?

Difficult to say without benchmarking. I can't recall how long the
battery lasted on my dapper system compared with edgy for example.

> * Do glxgears and CPU Burn-In represent valid load tests?

IMO no, not at all. A real world test might be more "realistic". But
everyones "real world" is different. For me it might include a wifi
access point in use with evolution open, checking mail via IMAP
regularly. It would also include one or more ssh sessions and a browser
or two. None of that is going to load the CPU tremendously but would use
wifi and a little disk IO (storing mail headers for example).

When people run systems on a battery, do they really run their systems
flat out? Unlikely. I tend not to do video re-encoding on a system
that's running off battery because I know it's going to eat the power.

That said, the test is a comparative one between releases, not a
benchmark of real world usage, so in some ways at least it is valid.

> * Should we be concerned that 5.10 represents the lowest power draw
> from the kernel?

Only if the test is valid. Should we be developing a simple script that
kicks off some standard applications (like the ones outlined above) and
then logs battery state to a file periodically? I would recommend that
whatever versions are tested, they should be up to date with whatever
update-manager recommends, but other than that they should be pretty
clean installs. 

I'd like to see a comparison of the current supported releases - Dapper,
Edgy, Feisty and (soon) Gutsy, and then further, a comparison with Gutsy
after doing everything that powertop recommends.

> I've noticed in all their desktop screenshots, the update-manager was
> prompting for updates. I don't know of any updates regarded to improve
> power usage, but I think later versions will download and unpack,
> potentially adding a long set of updates to download and unpack in the
> background.

You could perform the tests only after the system has settled for a
while - after all updates have been processed, and update-manager has
done its checks.

Maybe we should have a little wiki page to gather this information?

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