This testcase is an augmented version of https://people-mozilla.org/~jmuizelaar/implementation-tests/dl-test.html that invalidates all elements on every frame. Profile: https://perfht.ml/2rbfPax We spend a lot of time in ClientTiledPaintedLayer::InvalidateRegion, due to this line: > mValidRegion.Sub(mValidRegion, mInvalidRegion.GetRegion()); Recomputing mValidRegion on every single call is wasteful. We should find a way to skip this step until mValidRegion is actually needed.

Comment on attachment 8878229 [details] Bug 1368386 - Make ProgressiveUpdate's aInvalidRegion parameter const to make it a bit easier to reason about. https://reviewboard.mozilla.org/r/149572/#review154250

Comment on attachment 8878230 [details] Bug 1368386 - Make ProgressiveUpdate's aValidRegion parameter const to make it a bit easier to reason about. https://reviewboard.mozilla.org/r/149574/#review154272

Comment on attachment 8878231 [details] Bug 1368386 - Add PaintedLayer::InvalidateWholeLayer(). https://reviewboard.mozilla.org/r/149576/#review154276

Comment on attachment 8878232 [details] Bug 1368386 - Make PaintedLayer::mValidRegion private so that its access can be tightly controlled. https://reviewboard.mozilla.org/r/149578/#review154632

Comment on attachment 8878233 [details] Bug 1368386 - Only call mInvalidRegion.GetRegion() when an up-to-date valid region is requested. https://reviewboard.mozilla.org/r/149580/#review154634

Pushed by mstange@themasta.com: https://hg.mozilla.org/integration/autoland/rev/983ebee83aed Make ProgressiveUpdate's aInvalidRegion parameter const to make it a bit easier to reason about. r=mattwoodrow https://hg.mozilla.org/integration/autoland/rev/02720536f017 Make ProgressiveUpdate's aValidRegion parameter const to make it a bit easier to reason about. r=mattwoodrow https://hg.mozilla.org/integration/autoland/rev/43cbca8c663e Add PaintedLayer::InvalidateWholeLayer(). r=mattwoodrow https://hg.mozilla.org/integration/autoland/rev/11b6836cf3eb Make PaintedLayer::mValidRegion private so that its access can be tightly controlled. r=mattwoodrow https://hg.mozilla.org/integration/autoland/rev/b4d533bb18fc Only call mInvalidRegion.GetRegion() when an up-to-date valid region is requested. r=mattwoodrow

https://hg.mozilla.org/mozilla-central/rev/983ebee83aed https://hg.mozilla.org/mozilla-central/rev/02720536f017 https://hg.mozilla.org/mozilla-central/rev/43cbca8c663e https://hg.mozilla.org/mozilla-central/rev/11b6836cf3eb https://hg.mozilla.org/mozilla-central/rev/b4d533bb18fc