1681346 - Deduplicate system fonts in WebRender

Status: RESOLVED DUPLICATE of bug 1758555

(Core :: Graphics: WebRender, enhancement, P3)

Description

[Nicolas Silva [:nical]]

I suspect that we create them once per process that use them.

Instead of creating/deleting them when we get ResourceUpdate::AddFont/DeleteFont, we should keep add a cahce of existing system fonts by name with a reference count. When requesting glyphs we should use the deduplicated handle to avoid extra rasterization.

Comment 1

[Jeff Muizelaar [:jrmuizel]]

This will become more important with Fission as we'll have lots of processes.

Comment 2

[Markus Stange [:mstange]]

The reality is actually worse: We don't only create them once per content process, we even create them once per tab, even for tabs that share the same process. For example in bug 1683975, we run into performance problems because creating new system font objects in WR for every new tab is quite slow.

Comment 3

[Jeff Muizelaar [:jrmuizel]]

I could imagine this working as follows:

• Change things so that we don't key the glyph cache on the font-key and instead use some per font key. This can essentially be what ever the font key maps to.
• Keep a cache that maps (serialized system font, font)