468726 - Overall slow rendering after resizing website on Linux

Status: RESOLVED WORKSFORME

(Firefox :: General, defect)

Description

[Tomasz Sałaciński]

User-Agent:       Mozilla/5.0 (X11; U; Linux i686; pl; rv:1.9.1b2) Gecko/20081201 Firefox/3.1b2
Build Identifier: Mozilla/5.0 (X11; U; Linux i686; pl; rv:1.9.1b2) Gecko/20081201 Firefox/3.1b2

The full page zoom introduced a performance problem on Linux machine (problem doesn't exist on a Windows machine).

The problem is, that in overall, firefox gets slow if the page size is not at the default using full page zoom.

For example, try going to the URL I've provided and try to move the widgets on the right side. If you're at default zoom level, it superfast.

If you'll try to zoom though, it starts to work slow. No matter, if you zoom in or out.

Some pages start to scroll jerky (while at default zoom level scrolling is superfast on every website I've seen - I am talking about Firefox 3.0.4, not the beta I am using, because it works the same). Some pages start to be less responsive on "hover" elements. The known fixed div problem is happening only on not-default zoom level.

Basically, Firefox works great only on default zoom level. After zooming - the performance of some elements is dropped.

This doesn't happen if "Zoom text only" option is enabled. It seems to be related to scaling images. If the website doesn't contain any images, it scrolls/works/renders as fast as normal.

Reproducible: Always

Steps to Reproduce:
1. Go to url provided
2. Try to move the widgets on the right
3. Zoom in or out using full page zoom and try to move the widgets again
4. You can try also iGoogle (www.google.com/ig - you're not moving any images, only widgets drawn with css, but the performance is still slow)
Actual Results:  
Overall performance is dropped when full page zoom is enabled and the site is zoomed.

Expected Results:  
Firefox should behave the same no matter what is the zoom level.

This is not a problem with my setup (because I worked on many Linux machines and all behave the same, no matter if this is intel/nvidia/nv/ati driver).

Even if I'll shrink the page to the smallest possible (so widgets are taking only few pixels of space) - it's still slow.

Comment 1

[Tomasz Sałaciński]

By the way - it might be leaking memory? After resizing the website to the smallest size possible, restoring the default zoom level doesn't help. Restarting Firefox helps.

Comment 2

[Tomasz Sałaciński]

Hmm... seems to be fixed in 3.5b4. Even the slowest websites work like a charm now! This version ROCKS and it's superfast in Linux too. Thanks!

Comment 3

[Tyler Downer [He/Him]]

I am glad your issue has been resolved, but that makes this bug WORKSFORME. FIXED is only for a bug that has had a known patch checked into the tree, which has not happened in this case.

Comment 4

[Tomasz Sałaciński]

Hello,

I just want to tell you that 3.5 version is very fast too. I've tested it on different computer (both with Fedora 11) and it works like a charm.

And for the patch:
I've read somewhere (can't remember where, sorry) that Firefox 3 had issue with artifacts when page was resized, that's why Mozilla Devs tried a workaround that made the pages look great but killed the performance when the page was resized. This seems to be dropped as I can see artifacts again in Firefox 3.5, but it boosted the performance.

Also, resize speed is much faster because of a lot better font caching.