923011 - Avoid copying data in GetSourceSurfaceForSurface

Status: NEW

(Core :: Graphics, defect)

Description

[Matt Woodrow (:mattwoodrow)]

The semantics of GetSourceSurfaceForSurface don't require us to copy the data, but we often end up calling CreateSourceSurfaceFromData which makes a copy.

On OSX at least, we hit this fairly often, so it seems worth trying to fix.

Very quick test to measure performance: https://tbpl.mozilla.org/?tree=Try&rev=ef18b616b25a

Looks like we could get a 2% (4mb) reduction in tp5 memory usage, and a 4% tscrollx win. Not huge, but probably worth having.

Bas, any thoughts on what you'd want the API to look like for this?

Comment 1

[Matt Woodrow (:mattwoodrow)]

Turning on azure content for OSX 10.6 regressed the tp5 memory usage by 2.8% (5.7mb), so fixing this would get most of that back.

I assume that azure content for 10.7/8 had a similar regression.