1509158 - Make Text Drawing simpler and faster

Status: NEW

(Core :: Graphics: WebRender, enhancement, P2)

Description

[Jeff Muizelaar [:jrmuizel]]

We spend quite a bit of WebRender display list building time going through nsTextFrame::DrawText. I suspect this code could be simplified and sped up further.

One option is to move more work into TextRun creation. See bug 1507975.
I'll continue to investigate what else there is to do.

Comment 1

[Jeff Muizelaar [:jrmuizel]]

As part of my investigations I saw 8.8% of nsDisplayText::RenderToContext being spent in nsTextFrame::EnsureTextRun. It looks like at least half of the time in this function is spent on
   if (textRun->GetFlags2() & nsTextFrameUtils::Flags::TEXT_IS_SIMPLE_FLOW) {
where I expect we're cache missing on the textRun for the first time and there's not much we can do here except improving our cache behaviour.