614167 - Investigate JS performance on "Prototype - writeAttribute" dromaeo test

Status: RESOLVED INCOMPLETE

(Core :: JavaScript Engine, defect)

Description

[Boris Zbarsky [:bzbarsky]]

We're slower than the competition, and a profile shows 82% of time at least spent in JS code.  

There's some taking stub calls to deal with DOM getters, lots of SetElem, Arguments, GetElem, NewInitObject, etc stub calls.  FixupArity, TypeOf stubs, NewArray.

And 18% of the time is in mjit-generated code, too.

The Arguments thing us 7% of the time here (mostly the malloc, actually), and shows up in all the Prototype stuff.

Comment 1

[Andrew McCreight [:mccr8]]

DOM bindings have been rewritten since 2010, and the JIT have been rewritten about 5 times since then. If there are still issues we care about, let's file new bugs.