[webkit-dev] JS binding wapper pointers: inline vs. separate hash table

[Maciej Stachowiak]

On Oct 1, 2008, at 4:48 PM, Peter Kasting wrote:

> On Wed, Oct 1, 2008 at 4:40 PM, Maciej Stachowiak <mjs at apple.com>  
> wrote:
> Do we have any measurements of the performance benefit?
>
> Copying verbatim Feng's post on this from the other thread into this  
> one:

Oops, I missed that.

>
> These Node properties all return a DOM node, and it loops several
> times to minimize the overhead of other JS constructs.
> I reused Dromaeo framework to run the test. The test page has ~4600
> nodes. Using Dromaeo framework to run the test along, I observed that
> with Peerable cache, it is about 7~8% faster. When the test with other
> Dromaeo tests, I observed that Peerable was 25% faster, but other
> tests either faster or slower, so I cannot tell if that's because of
> real impact of caching or some other effects. One thing for sure is
> that when running whole Dromaeo tests, the memory usage went to to
> 430+MB. That's may have an effect.

Sounds promising, though I'd like to see a test that combines some  
mutation with pure getters.

It definitely sounds like it is worth experimenting with inline  
wrapper pointers only for selected classes, not for all RefCounted (or  
even for all bindable classes). Sounds like that could give a lot of  
the potential speed win, without nearly as much memory cost.

Regards,
Maciej

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