What is the performance optimization of the Brendan Eichs model?

Question

In the end, Steve Egges essay on the prototype template , he says,

Brendan H.H. came up with a surprisingly smart performance optimization for the property template, which he told me about back in January. I was ready to publish this article, but I told him that I could hold on until he talked about optimizing it. From time to time he calls me and tells me "any day."

Brendan, this is October, damn it!

This note was written almost five years ago, but I did not seem to find any information on what Eichs optimization is. Did he or anyone else post the improvement mentioned by Yegge?

Answer 1

I went digging around starting with the Brendan tweet mentioned in another answer, and ended up on this blog post from '08 . Summarizing:

Many tests show that SpiderMonkey is significantly faster than Tamarin. This is mainly due to how SpiderMonkey accesses the properties of the object. SpiderMonkey implements a figurative idea. A form is a unique identifier that details the structure of an object and allows you to quickly find a given property. With a few bits of operations, given the shape of the facility and the current program location, we can find the property address.

Check out the blog post for more details and links to the actual code from now on.

Answer 2

Via Twitter , Brendan said,

in SpiderMonkey, as you know. Property trees => shapes that look like hidden classes, but with lots of sections.

So make what you want out of it.