406692 - DOM node wrapping optimization (nsNodeSH::PreCreate()).

Status: RESOLVED FIXED

(Core :: DOM: Core & HTML, defect)

Description

[Johnny Stenback (:jst)]

Attachment: Add a fast path from nsIDocument to its JSObject.

nsNodeSH::PreCreate() keeps showing up as a hotspot in profiles (see bug 375225), the expensive part of that is that we wrap the nodes parent, which again wraps its parent etc, going on depending what the parent chain should be etc. The common case by far is that a node's parent (as far as JSObject parent goes) is the document, so thus if we had a fast path from an nsIDocument pointer to its JSObject, we wouldn't need to wrap the document. Fixing that alone shaves off about 5% of the XPConnect overhead in bug 375225.

Comment 1

[Johnny Stenback (:jst)]

Fix checked in.