[Development] Qt 5.2 Beta - is it really much slower to parse qml/javascript on android?

Simon Hausmann simon.hausmann at digia.com
Tue Oct 29 15:40:17 CET 2013


On Tuesday 29. October 2013 10.31.16 Felipe Crochik wrote:
> summary: some very simple "qml" code now is taking 4 seconds to "parse" and
> get to the "component.onCompleted" on android. It is instantaneous using
> qml 1.0/old necessitas. What is the best way to profile and found why?
> Anybody seeing a much longer "parsing time"? can it be related to the
> replacement of V8?

Quite likely, and also quite likely to be a bug :)

Can you elaborate a bit on some details? I'd be curious about the following:

* From when is your build of Qt?
* Is this a build for ARMv7 or older?
* Are you importing bigger pieces of JavaScript using import? (nothing bad 
about it, merely curious)
* Can you help us identify if is it the type instantiation that is slow or the 
execution of Component.onCompleted itself? I.e. if you add a console.log at 
the beginning of Component.onCompleted, does it take 4s until you see that 
message or does it take 4s _after_ seeing it?



Simon
 
> longer version:
> I have this very simple game (
> https://play.google.com/store/apps/details?id=com.crochik.lockcode) that I
> had created using qml 1.0 and deployed to android using one of the alpha
> releases of necessitas/qml 1.0. The game is just qml and javascript, using
> only basic qml components.
> 
> I just created a new "qt quick 2.0" project, copied the qml files to the
> project and changed the "headers"  to use qt quick 2.0 (instead of 1) and
> now it takes 4 seconds to "parse the qml" and get to the top level
> component.oncompleted. I am using a loader to "measure" the time between
> setting the loader source and getting to the "oncompleted" on the "loaded
> top level component"
> 
> Thanks,
> Felipe




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