Re: Mutation events - slowness examples

Sean Hogan wrote:
> I don't know what would count as a performance sensitive web-app.

Just as a data point, Gecko trunk had a bug earlier today where we 
accidentally introduce a performance regression on removing table rows. 
  The bug was easily caught because the regression made removing a table 
row O(N) in number of rows and it immediately turned out that all sorts 
of pages out there sort multi-thousand-row tables by reordering the row 
nodes in the DOM.

Which means that they're doing thousands to tens of thousands of DOM 
mutations.  And the time required needs to stay small (under 200ms, 
ideally, since that's about whether the user starts perceiving the 
operation as laggy).

That's the sort of thing that we're worried about here, I think...

-Boris