mirror of
https://github.com/mozilla/gecko-dev.git
synced 2024-12-03 18:47:53 +00:00
64e0a7e0fd
In order to create less WebRenderLayerScrollData currently we use a deferred transform item https://searchfox.org/mozilla-central/rev/593c49fa812ceb4be45fcea7c9e90d15f59edb70/gfx/layers/wr/StackingContextHelper.h#82 We don't need a WebRenderLayerScrollData for every transform because a lot of transforms don't contain any ASRs, so the created WebRenderLayerScrollData would be useless. However this optimization can lead to us creating a lot more WebRenderLayerScrollData later if the transform does contain ASRs. For example, if there is a transform, and then inside that is a ASR, and inside the ASR is a lot of small transforms, we end up having to create a WebRenderLayerScrollData for every little transform which don't contain any ASRs. This is doing the opposite of what the optimization intended. WebRenderLayerScrollData creation happens during the CreateWebRenderCommands phase, so the display list build phase is complete, and we can tell cheaply if a transform contains any ASRs during display list building. So we just record that and use that to inform our decision about when to defer the transform item or not. This optimization drastically reduces the total number of WebRenderLayerScrollData that we create during a full run of speedometer3 (summing the number created each paint over every paint). In my testing it went from 12-13k to 2-3k. Mostly subtests fell into two buckets: a single digit number of WebRenderLayerScrollData to begin with and this patch didn't change that, and 100 WebRenderLayerScrollData down to single digits after this patch. So the savings are concentrated in a few subtests that hit the described behaviour above. I compared a profile before and after this patch of 10 runs of speedometer3, this patch saved 100 samples/ms serializing WebRenderLayerScrollData, which was what I expected based on how long serialization took before the patch combined with how many WebRenderLayerScrollData we were avoiding. The whole run took about 100,000 samples/ms, so this should hopefully be good for about 0.1% improvment. There is also potential savings in other areas outside of serialization step but that was a little harder to measure. Differential Revision: https://phabricator.services.mozilla.com/D197446 |
||
|---|---|---|
| .. | ||
| base | ||
| build | ||
| docs | ||
| forms | ||
| generic | ||
| inspector | ||
| ipc | ||
| mathml | ||
| media | ||
| painting | ||
| printing | ||
| reftests | ||
| style | ||
| svg | ||
| tables | ||
| tools | ||
| xul | ||
| moz.build | ||