Ok, fixed the perf regression. Here's the commit:
http://dev.jquery.com/changeset/6261
In Firefox 3.0.6 I'm now getting (on my local copy):
Query version used = 1.3.3pre
Total number of DIVs = 1000
Paragraphs per DIV = 500
$("#div500 p") = 19ms
$("p", "#div500") = 2ms
$("#div500").find("p") = 1ms
$("#div500 > p") = 6ms
$("#div500").children("p"); = 19ms
I'll dig around tomorrow and see if I can still get some juice out of
"#div500 p".
The issue is that $("#div500") takes a *ton* of shortcuts to try and
make ID selectors faster - which is good since that's what developers
tend to use a lot - but in the case of $("#div500 p") we have to dip
down into the selector engine which has to be more thorough in its
checks. I've cut out just about everything that I can to make
#id-rooted queries faster, but I'll keep checking to see if there's
something that I'm overlooking.
As far as .children() goes, I have that on the list to optimize (along
with next/prev/siblings/parent/parents/etc.).
And I'll tackle the IE regression tomorrow morning, as well.
Thanks for these tests - it's stuff that I've been meaning to get
around to for a while now but it's good to have some easy-to-spot
targets.
--John
On Wed, Feb 25, 2009 at 7:21 PM, John Resig <jere...@gmail.com> wrote:
>> WOW! Check out the last 2 tests, John. Syntax #4 takes 512-times
>> longer than #5! I think this code needs a little TLC too ;)
>>
>> It was also interesting that $("#div500").children("p") is 10-times
>> slower than $("#div500").find("p"). So I added one final test using
>> childNodes and filter() to see if I could beat .children()...
>
> Oh right, this is a regression to what I just did - I can tweak that.
> I'll look in to it tonight.
>
> --John
>
