[OLPC-devel] OLPC theme benchmarked

[Jim Gettys]

Is this with Jordan's new driver?  If so, we may have run into a slow
path that might be able to be sped up....  If not, it is time to install
his driver....
                           - Jim 

On Wed, 2006-08-02 at 15:21 +0200, Manu Cornet wrote:
> 
> Hi !
> 
> I have been coding a small "torture" application for GTK themes [1],
> which mainly does two things: 1) crash test the engine by calling all
> the GTK paint functions with unsual parameters and 2) measure the time
> the theme takes to create/map/expose/resize/destroy widgets (with help
> from Federico's widget profiler's infrastructure).
> 
> While fixing the OLPC theme to pass my crash test [2], I noticed that it
> was quite a bit slower than I expected, so I thought that precise time
> measures would be interesting. I hope this is useful, it will definitely
> help me in the next few days :)
> 
> 
> The full report is available as a spreadsheet [3]. Before writing a
> short analysis, a few disclaimers:
> 
> * The main point of this benchmarking is to have a record of the current
> speed (so that we can see how it evolves when some more work has been
> done). The theme is a work in progress, and therefore understandably
> still very slow compared to more polished ones.
> 
> * I tried my best to make the testing conditions as stable as possible:
> same computer (of course), same programs running in the background,
> tests performed within a small time window, etc.
> 
> * The different time measures correspond to the few important events in
> a widget's life: create, map, expose, destroy. The "expose with resize"
> corresponds to resizing the widget a lot of times (from a very small
> size to a very big size) and measuring the expose time for each size.
> 
> * Each cell of the document is an amount of time (in seconds) averaged
> from about 80 iterations of the same event, on the same type of widget.
> 
> * These are only observations, not explanations. Make the slow parts
> faster will be the next job!
> 
> * Absolute time values aren't that useful, but ratios are more
> interesting.
> 
> 
> Okay, so a few observations:
> 
> * Create : ratios vary from 0.92 to 1.07, showing that create time is
> pretty much the same for all themes, for each type of widget.
> 
> * Mapping a widget takes the OLPC theme about twice as much time as
> Clearlooks (or HighContrast).
> 
> * Destroy is always slightly (30 %) faster on OLPC than on Clearlooks,
> but slower than HighContrast (about 1.4 ratio). Destroy time are pretty
> much the same between OLPC and Human (Ubuntu's theme) -- ratio ~ 1.
> 
> * Expose is a bit slower (1.9 ratio, and sometimes a little faster) with
> OLPC than with Clearlooks or HighContrast, but faster than Human.
> 
> * Expose with resize is the most CPU-consuming task, and therefore
> probably yields the most significant results. And the OLPC theme doesn't
> do well with this one: it is from 30 to 130 times slower than Clearlooks
> (50 times on average), and 35 times slower than Human.
> 
> I'll spend the next few weeks (along with the other developers of the
> theme) trying to bring those numbers down while still aiming towards
> Diana's great mockups :o)
> 
> Cheers,
> Manu
> 
> [1]
> http://wiki.laptop.org/go/GTK_for_OLPC#GTK_theme.2Fengine_torturer_and_crash_tester
> 
> [2]  See the report at
> http://www.manucornet.net/pub/olpc/log_olpc_theme_torture.txt
> 
> [3] http://www.manucornet.net/pub/Themes_performance.ods
> 
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-- 
Jim Gettys
One Laptop Per Child