[MeeGo-dev] Making meego fast - quick tests and lots of input needed

[Gary Birkett]

Hi,

One of the big things people want nowadays with an OS is speed.
They expect a nice fast solid slick experience.

Last night during the discussions in IRC, performance was mentioned and how
it is lacking in meego at the moment.
Now, we can talk about it being an alpha and a beta and unreleased and its
going to get faster all we want, but it has to get faster from all angles.
There are going to be all sorts of different optimisations available and we
have to start somewhere.


On the n810, I used to have the capability of running in alternative
resolutions.
I could run my applications at full high resolution which did not always run
perfectly quickly and drained the battery a bit more
Or I could change to a lower resolution and carry on running exactly the
same using MUCH less CPU and battery

This also had the drastic effect of making it run *REALLY REALLY FAST*

One of the things about Meego is that it is designed to be run on different
handsets with different screen resolutions.
Some of them will be lower than others and some will be higher.

To gain maximum performance on the reference N900 and to test out this
resolution invariance,
I would like to find out how to change the resolution in Meego.

Now, stskeeps told me that libmeegotouch does infact support variable
resolutions:

<lcuk> and working out how to operate in alternative resolutions *WILL* be
needed when you get other devices onboard
<Stskeeps> lcuk: libmeegotouch already runs in alternative resolutions
<Stskeeps> check devices.conf sometime

However, when I have asked about this in the past have heard that there are
some issues with applications not playing too well with variations.
These if true would need to be sorted, but as a quick simple test, I opened
liqbase on my n900 and tried changing the resolutions and rerunning.

<lcuk> I just did some testing in liqbase
<lcuk> and running liqbase at *800*480 *gets a framerate doing a certain
task at *45fps*
<lcuk> running same task at *640*480 *gives me *55fps*
<lcuk> I do not have capbility to test this [in meego]
<lcuk> can someone PLEASE try on n900 changing the parameter stskeeps
mentioned
<lcuk> and tell me if it does change resolution
<lcuk> and if its a valid strong improvements?
<Stskeeps> lcuk: that isn't what sets screen resolutions, just what
resolutions it's expected to work with :P
<lcuk> so then setting that parameter is first step
<lcuk> what else? - even accepting a black line down the side
<lcuk> is it entirely down to the graphics driver?
<lcuk> the yuv overlay mode can be coerced into stretch to fit (it just did
it for me now)
<lcuk> I have never managed or tried with rgb

Quite drastic improvement for a 5 minute test!!!

Drawing 20% less pixels gives a speedup of ~20%

Now your turn Meego, how much improvement can be got by changing the
resolution?
how is it done?  stskeeps mentioned in IRC about the parameter just being
the libmeegotouch stuff
so there will be more needed I bet.
what problems are there?

What other mechanisms can be tried???

where else can we get rid of large chunks of sluggishness?

Gary
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