I'm not super familiar with the intricacies of paint scheduling, so I'll stop digging at this point. I think/hope the profiles in comment 8-9 should have enough info for someone to dig further, though. CC'ing tnikkel, mstange, and emilio who might have thoughts/insights here. tl;dr answers to comment 5: "what's the profile measuring": first paint (via MozAfterPaint which corresponds to FirstContentfulComposite) "do we need to worry": yes. the profiles seem to legitimately show substantially-delayed paint operations here.
Bug 1783674 Comment 10 Edit History
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I'm not super familiar with the intricacies of paint scheduling, so I'll stop digging at this point. I think/hope the profiles in comment 8 - comment 9 should have enough info for someone to dig further, though. CC'ing tnikkel, mstange, and emilio who might have thoughts/insights here. tl;dr answers to comment 5: "what's the profile measuring": first paint (via MozAfterPaint which corresponds to FirstContentfulComposite) "do we need to worry": yes. the profiles seem to legitimately show substantially-delayed paint operations here.