Re: nsGenericElement::InsertBefore performance

Boris Zbarsky wrote:
> Andreas Pflug wrote:
>   
>> Initialisation will still be several magnitudes faster, since all 
>> controls will use their readily compiled handlers.
>>     
>
> Of course XBL also uses precompiled handlers...  The real issue here is not the 
> handlers.
>
>   
>> I see the problem that XUL/XBL is used as if it was as cheap as it is 
>> with typical gui lib
>>     
>
> Putting 8 images in a dialog is cheap with a typical GUI lib?
>   
Yes. You'd certainly have a prerequisite preparation of loading the 
image into some useful memory structure, easily cacheable, but the act 
of adding it to the windows list is a very cheap step. The windowing 
system doesn't need to resolve how to display the item at that moment, 
instead it is given a pointer to the function that will handle it.
Actually, I tested cal-mon-day-item with most images removed, and didn't 
find a noticeable difference, images are the cheap part.
>   
>> but using typical programming 
>> techniques will lead to poor results (unfortunately demonstrated by 
>> Sunbird/Lightning, which appears as some kind of Mozilla demo app to me 
>> since it's integrated into the mozilla source tree).
>>     
>
> Uh... That's a really really bad assumption.  _Really_ bad.
>
> My basic point was that the code involved is just poorly written if one is at 
> all interested in performance.
>   
So you believe nicely written code would be 100 times faster?
>
>
> You just described the XUL prototype system.  Which XBL uses, in fact, when 
> cloning the subtree, if the subtree is XUL.
>
>   
>> Easy, no? ;-)
>>     
>
> Not easy, but done!  ;)
>   
So if stuff is reused, why does it take 20k memory and 5ms to create a 
simple reference?

> See above.  Cloning XUL produces lightweight XUL elements that point to the 
> prototype element...  It's already optimized for exactly this use case.
>   
I must be missing something. Producing 22 lightweight XUL elements takes 
5 ms?
Refererencing your old mail, you found a lot of time is spent in the 
constructor, why is it re-executed? Why is "loading the XBL bindings" 
re-executed?

Regards,
Andreas