Re: nsGenericElement::InsertBefore performance

Boris Zbarsky wrote:
> Andreas Pflug wrote:
>  
>> The testcase is sunbird CVS (VC2008), one calendar, one visible event in
>> month view. Toggle the calendar off and on.
>>     
>
> That's not really a testcase, because if nothing else I have no idea 
> what code is running.... 
Well with a .mozconfig of
. $topsrcdir/calendar/sunbird/config/mozconfig
ac_add_options --disable-javaxpcom
ac_add_options --enable-chrome-format=flat
ac_add_options --enable-debug
ac_add_options --disable-optimize

make -f client.mk checkout; make -f client.mk build.
>  Ideally, the testcase would be a standalone XUL file (plus possibly 
> the XBL bindings needed) that I'd be able to run in any Gecko browser.   
Maybe somebody with more sunbird/XUL knowledge can provide this.
>   If sunbird is the only way to reproduce, you need _much_ more clear 
> instructions to reproduce (click-by-click instructions).
>   
Select month calendar view, create one simple event, then click the 
calendar's checkbox on the left side to "off", start profiler, click 
calendar on, stop profiler.

> oth shark (OSX) and sysprof or jprof (linux) can generate those; I'm 
> sure there's a profiler for Windows that can too...
>   
Yes, the VS2008 team edition, I don't have it.

Currently, things work like this:

for (i=0; i < 1000 ; i++) {
   var box=document.createElementNS("...", "calendar-month-day-box-item");
   box.setAttribute(...)
   this.dayitems.insertBefore(box, null);      // 5 ms per call
}

So actually the same initialization stuff is repeated all over again. I 
wonder if some kind of caching mechanism could be invented:

var cachedBox=null;
for (i=0; i < 1000 ; i++) {
   if (!cachedBox) {
      cachedBox = document.createElementNS("...", 
"calendar-month-day-box-item");
      cachedBox.setAttribute(...)
      document.prepareForRendering(cachedBox);   // may take a while
   }
   var box=cachedBox.createCacheReference();
   this.dayitems.insertBefore(box, null);
}

Regards,
Andreas