I reproduced this on macOS. I suspect a lot of canvas's are being created or something like that. Here's a stack from Instruments: 39.63 s 85.7% 1.00 ms mozilla::dom::CanvasRenderingContext2D::DrawImage(mozilla::dom::HTMLImageElementOrSVGImageElementOrHTMLCanvasElementOrHTMLVideoElementOrImageBitmap const&, double, double, double, double, double, double, double, double, unsigned char, mozilla::ErrorResult&) 27.70 s 59.9% 1.00 ms mozilla::dom::CanvasRenderingContext2D::EnsureTarget(mozilla::gfx::RectTyped<mozilla::gfx::UnknownUnits, float> const*, bool) 27.63 s 59.7% 0 s mozilla::gfx::DrawTargetSkia::ClearRect(mozilla::gfx::RectTyped<mozilla::gfx::UnknownUnits, float> const&) 27.62 s 59.7% 1.00 ms SkCanvas::drawColor(unsigned int, SkBlendMode) 27.62 s 59.7% 1.00 ms SkCanvas::drawPaint(SkPaint const&) 27.62 s 59.7% 0 s SkCanvas::internalDrawPaint(SkPaint const&) 27.62 s 59.7% 0 s SkBitmapDevice::drawPaint(SkPaint const&) 27.62 s 59.7% 1.00 ms SkDraw::drawPaint(SkPaint const&) const 27.62 s 59.7% 8.04 s avx::rect_memset32(unsigned int*, unsigned int, int, unsigned long, int) 19.43 s 42.0% 0 s user_trap 14.60 s 31.5% 791.00 ms 0xffffff80003a7a70 5.44 s 11.7% 412.00 ms vm_fault_enter
Bug 1738290 Comment 13 Edit History
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I reproduced this on macOS. I suspect a lot of canvas's are being created or something like that. Here's a stack from Instruments: ``` 39.63 s 85.7% 1.00 ms mozilla::dom::CanvasRenderingContext2D::DrawImage(mozilla::dom::HTMLImageElementOrSVGImageElementOrHTMLCanvasElementOrHTMLVideoElementOrImageBitmap const&, double, double, double, double, double, double, double, double, unsigned char, mozilla::ErrorResult&) 27.70 s 59.9% 1.00 ms mozilla::dom::CanvasRenderingContext2D::EnsureTarget(mozilla::gfx::RectTyped<mozilla::gfx::UnknownUnits, float> const*, bool) 27.63 s 59.7% 0 s mozilla::gfx::DrawTargetSkia::ClearRect(mozilla::gfx::RectTyped<mozilla::gfx::UnknownUnits, float> const&) 27.62 s 59.7% 1.00 ms SkCanvas::drawColor(unsigned int, SkBlendMode) 27.62 s 59.7% 1.00 ms SkCanvas::drawPaint(SkPaint const&) 27.62 s 59.7% 0 s SkCanvas::internalDrawPaint(SkPaint const&) 27.62 s 59.7% 0 s SkBitmapDevice::drawPaint(SkPaint const&) 27.62 s 59.7% 1.00 ms SkDraw::drawPaint(SkPaint const&) const 27.62 s 59.7% 8.04 s avx::rect_memset32(unsigned int*, unsigned int, int, unsigned long, int) 19.43 s 42.0% 0 s user_trap 14.60 s 31.5% 791.00 ms 0xffffff80003a7a70 5.44 s 11.7% 412.00 ms vm_fault_enter ```