1628105 - Rasterize blobs in bigger buffers

Status: NEW

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

Description

[Nicolas Silva [:nical]]

We get a lot of overhead from rasterizing blobs in many small tiles, and not that much parallelism to make up for it.

• One way to go about it is to increase the tile size, from 256x256 to maybe 512x512 (Note that larger sizes won't play nice with the texture cache's atlas allocator). If we do this we may want to support per-tile dirty rects.

• Another approach is to keep the 256x256 tiling scheme in the texture cache, but allow rasterizing several tiles at the same time in the blob rasterizer. For example when rasterizing 6x10 tiles we could rasterize them row by row in larger 1536x256 buffers and still upload them into 256x256 tiles in the cache.