561357 - Large/complex SVGs lock up browser interface when loading, redrawing window.

Status: RESOLVED WORKSFORME

(Core :: SVG, defect)

Description

[Michael]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.3a5pre) Gecko/20100423 Minefield/3.7a5pre (.NET CLR 3.5.30729)
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.3a5pre) Gecko/20100423 Minefield/3.7a5pre (.NET CLR 3.5.30729)

When visiting http://michaelt.uwcs.co.uk/unviewboxed.svg the browser consumes 100% CPU and the user interface becomes unresponsive until the image is fully drawn on screen.

This takes several minutes on my computer.

This also happens when I change tabs away from the svg then back to it; when I change windows; and so on.

Reproducible: Always

Steps to Reproduce:
1. Use a computer with, say, a Pentium 4 or Atom processor.
2. Load system monitor to view CPU usage.
3. Visit http://michaelt.uwcs.co.uk/viewboxed.svg
4. Observe the locked-up state of the browser's user interface and 100% CPU usage.
5. Try changing between tabs (and between windows) so the svg gets redrawn.
Actual Results:  
Takes several minutes to draw the image, change tabs, redraw window.

Expected Results:  
One of:
(a) the rendering to abort after about 60 seconds
(b) an error message (similar to the unresponsive script error message) after the same time
(c) the rendering to take place in a separate thread so the user interface doesn't lock up.

Also, optionally,
(d) caching the rendered image as a bitmap, so that images which are slow to initially render do not have to be re-rendered every time the window is redrawn (such as when changing tabs or changing windows).

Has obvious denial-of-service implications.

Comment 1

[Michael]

Attachment: A large SVG, which may crash or lock up the browser.

Comment 2

[Boris Zbarsky [:bzbarsky]]

> (a) the rendering to abort after about 60 seconds

That may be difficult if the time is actually spent in OS drawing code.

> (c) the rendering to take place in a separate thread so the user interface
> doesn't lock up.

Being worked on: https://wiki.mozilla.org/Electrolysis

> (d) caching the rendered image as a bitmap

Being worked on: https://wiki.mozilla.org/Gecko:Layers

Comment 3

[Robert Longson [:longsonr]]

Freezes Opera too FWIW.

Comment 4

[Robert Longson [:longsonr]]

The test file is consists of around 19500 rects. This is an example.

<rect style="fill:none;stroke:#000000;stroke-width:2px" width="0.000008" height="0.000011" x="-1.558505" y="52.383966" />

Comment 5

[Jonathan Watt [:jwatt]]

A profile of me zooming in multiple times on the SVG shows 90%+ of the time spent under DrawTargetSkia::StrokeRect. There's not much we can do to improve that.

https://perfht.ml/2nR7cPb

Also we don't seem to perform so differently to Chrome.