We have bugs all over the place to track display item layer conversions. Let's make this the default meta. The giant list of items: https://public.etherpad-mozilla.org/p/wr-plan#lineNumber=167 As of today: Open - Background ThemedBackground nsDisplaySVGGeometry Gradients - Bug 1347469 - Add gradient border support in quantum render. Background image gradients - https://bugzilla.mozilla.org/show_bug.cgi?id=1341101 AltFeedback - https://bugzilla.mozilla.org/show_bug.cgi?id=1345388 Bullet - https://bugzilla.mozilla.org/show_bug.cgi?id=1349500 ColumnRule - https://bugzilla.mozilla.org/show_bug.cgi?id=1344079 TableBorderBackground - https://bugzilla.mozilla.org/show_bug.cgi?id=1344082 Done Image - https://bugzilla.mozilla.org/show_bug.cgi?id=1345053 - Done Text - https://bugzilla.mozilla.org/show_bug.cgi?id=1329314 - Done ButtonBorderBackground - https://bugzilla.mozilla.org/show_bug.cgi?id=1343979 - Done ButtonForeground - https://bugzilla.mozilla.org/show_bug.cgi?id=1344622 - Done CanvasBackgroundColor - https://bugzilla.mozilla.org/show_bug.cgi?id=1343450 - Done BackgroundColor - https://bugzilla.mozilla.org/show_bug.cgi?id=1349497 - Done Border - Bug 1322079 - Add support for border layers in WebRender LayerManager/Bridge code - Done Outline - https://bugzilla.mozilla.org/show_bug.cgi?id=1348755 Items that don't need work: https://bugzilla.mozilla.org/show_bug.cgi?id=1344002#c2 sDisplayTransform, nsDisplayBlendMode, nsDisplayBlendContainer, nsDisplayMask, nsDisplayOwnLayer, nsDisplayOpacity

Done: Box shadow inset - bug 1349843

Outer box shadows, almost done - 1347727

Background image - bug 1351242

Text overflow marker - bug 1351508 Bug 1351510 - Conver nsDisplaySolidColor to a WebRender Display Item Bug 1351511 - Convert nsSolidColorRegion to WR DisplayItems

A chart of how many times a display item of a certain type was created compared to all the display items that were created. We see that we don't actually have that many items. Top 10 are: 1) Layer event regions (27%) 2) text (26%) 3) Background color (13.5%) 4) background (5.8%) 5) border (5.6%) 6) Image (4%) 7) opacity (3.5%) 8) Transform (2.1%) 9) SVG Geometry (1.9%) 10) button border background (1.8%)

It'd also be interesting to see what percentage of display lists each type of display item is present in. eg There would only be one CanvasBackgroundColor per display list, so it is quite low down this list. But it is present in basically every page, (and takes up a large area) so is important that we convert it. I realise this particular example is already implemented, but there might be others.

I think it would give a more accurate picture to only count each display item once per page.

Note: please keep the status of DI up to date in this etherpad: https://public.etherpad-mozilla.org/p/wr-status

I did some local profiling to see what display items are actually slow. The list is surprisingly small. In order of importance: 1) Background 2) Text 3) Images 4) Box Shadows both inner and outer 5) nsDisplaySVGGeometry After browsing for quite some time, it's rare that we see other display items ever take more than 1 ms to render. Backgrounds wildly vary, but by far are much slower than every other item. Sometimes I've seen 300 +ms to render a background. Text is next, but most of the time takes 1-2 ms, with max of ~30ms. Next are images, usually take 3-4 ms with a max of ~8ms Finally box shadows with average 1-2ms with maxes of 5ms. SVG Geometry ~1-2ms. All tests done on Windows 10 w/ d2d on a late 2013 MacBook pro + NVidia gpu.

Also once in a very rare while, borders can sometimes take ~5ms.