Thanks! I can reproduce. Here's a profile with screenshots, and starting from the initial pageload: https://share.firefox.dev/3PxfWZR Notably, we spend a bit more time on frame construction to *build* the 400x400 matrix (3.5s in frame construction, shown as a long light-blue bar in my profile). The "Layout Cleanup" at reload time is simply us spending time (2.6s) destroying all of those frames that we created. Here's my profile, zoomed to focus on just that part (inside of "Layout tree destruction"): https://share.firefox.dev/4gP5ybX There are 2384 samples. Of those: * 2161 samples (91%) are in `nsTextControlFrame::Destroy` (here's the profile focused on those: https://share.firefox.dev/4gP4FjD ) * Most of those samples are in `mozilla::TextControlState::UnbindFromFrame` **creating some stuff**, in `mozilla::dom::HTMLInputElement::GetControllers`, which spends most of its time in `nsBaseCommandController::CreateEditorController` and `nsBaseCommandController::CreateEditingController` (note: those two functions have nearly the same name, differing only in "editOR" and "editING") * It seems a bit unexpected/unfortunate that we're spending time **creating stuff** as part of tearing down the world for this document.
Bug 1939344 Comment 3 Edit History
Note: The actual edited comment in the bug view page will always show the original commenter’s name and original timestamp.
Thanks! I can reproduce. Here's a profile with screenshots, and starting from the initial pageload: https://share.firefox.dev/3PxfWZR Notably, we spend a bit more time on frame construction to *build* the 400x400 matrix (3.5s in frame construction, shown as a long light-blue bar in my profile). The "Layout Cleanup" at reload time is simply us spending time (2.6s) destroying all of those frames that we created. Here's my profile, zoomed to focus on just that part (inside of "Layout tree destruction"): https://share.firefox.dev/4gP5ybX There are 2384 samples in layout tree destruction there. Of those: * 2161 samples (91%) are in `nsTextControlFrame::Destroy` (here's the profile focused on those: https://share.firefox.dev/4gP4FjD ) * Most of those samples (1372) are in `mozilla::TextControlState::UnbindFromFrame` **creating some stuff**, in `mozilla::dom::HTMLInputElement::GetControllers`, which spends most of its time in `nsBaseCommandController::CreateEditorController` and `nsBaseCommandController::CreateEditingController` (note: those two functions have nearly the same name, differing only in "editOR" and "editING"). Here's the profile filtered to see those: https://share.firefox.dev/3WhSLqi * It seems a bit unexpected/unfortunate that we're spending time **creating stuff** as part of tearing down the world for this document.