Gaussian blurs in librsvg 2.40.16 are largely not optimized, causing larger thumbnails for files that make heavy use of Gaussian blur to time out.
* 2.42.3 added minor optimizations (T193352)
* 2.43.3 optimized further
* 2.43.4 parallelized Gaussian blur
* 2.44.0 introduced more speed improvements
#### Known affected files
* https://commons.wikimedia.org/wiki/File:Jupiter_diagram.svg, 55s at [5000px x 2500px](https://upload.wikimedia.org/wikipedia/commons/thumb/b/b5/Jupiter_diagram.svg/5000px-Jupiter_diagram.svg.png)
* https://commons.wikimedia.org/wiki/File:Operation_Lavender_2017.svg, 98s at [2048px x 2048px](https://upload.wikimedia.org/wikipedia/commons/thumb/6/6e/Operation_Lavender_2017.svg/2048px-Operation_Lavender_2017.svg.png)
* https://commons.wikimedia.org/wiki/File:Third_imperial_Faberg%C3%A9_egg.svg, 3+ minutes at [2000px x 1664px](https://upload.wikimedia.org/wikipedia/commons/thumb/3/3a/Third_imperial_Faberg%C3%A9_egg.svg/2000px-Third_imperial_Faberg%C3%A9_egg.svg.png)
* https://commons.wikimedia.org/wiki/File:Dojikko2.3.svg at [802px x 535px](https://upload.wikimedia.org/wikipedia/commons/thumb/3/36/Dojikko2.3.svg/802px-Dojikko2.3.svg.png)
At least the first three are rendered in 10-15 seconds with librsvg 2.48 in the requested size mentioned above.
----
Reported on IRC regarding https://commons.wikimedia.org/wiki/File:Jupiter_diagram.svg which has relatively large dimensions in the SVG base image.
This 2000px thumbnail has already rendered fine:
https://upload.wikimedia.org/wikipedia/commons/thumb/b/b5/Jupiter_diagram.svg/2000px-Jupiter_diagram.svg.png
But the file: page links offer a 5000px thumbnail which does not render:
https://upload.wikimedia.org/wikipedia/commons/thumb/b/b5/Jupiter_diagram.svg/5000px-Jupiter_diagram.svg.png
It takes some seconds (30-ish?) then times out with an HTTP 500 error. Too many attempts hits rate limiting, returning a 429.
A sample request failure id:
{F24370968}