682221 - choppy scrolling on news.google when articles are expanded

Status: RESOLVED WORKSFORME

(Core :: Graphics, defect)

Description

[Luke Wagner [:luke]]

Recent changes to news.google.com make scrolling significantly more choppy.  Chrome stays smooth.

STR:
 1. go to news.google.com
 2. expand a news items by clicking on the summary text (not the title, which opens a new tab; clicking the summary should just make the item bigger)
 3. try to do smooth scrolling with a touchpad

Results:
Not smooth.  Tested on 2x2.66GHz MacBookPro.  Collapsing all the articles makes scrolling smooth.

I ran this under Shark:
43% under mach_kernel
  36% under mach_vm_copy
  5.5% under iokit_server_routine
10.2% under _cairo_quartz_*
2.4% nsAppShell::ProcessNextNativeEvent
1.5% SelectorMatches

Based on this I'll tentatively file under Graphics component.

Comment 1

[Luke Wagner [:luke]]

It's still pretty choppy on a pretty-fast MBP.

Comment 2

[Andrew McCreight [:mccr8]]

Sounds similar to the Google Reader problem, as mentioned here:

http://www.zdnet.com.au/googles-lovehate-approach-to-javascript-339326642.htm

I thought there was a bug on that, but I can't remember what it was.  But it doesn't seem to blow up memory or anything.

Marking as [Snappy:P2] because it could be a problem on a lot of Google sites, now that they are PlusOne everywhere.

Comment 3

[Marco Castelluccio [:marco]]

This shouldn't be a Snappy bug as we have bug 675866 to track improvements for scrolling and bug 100951 to track slow scrolling testcases.

Comment 4

[Luke Wagner [:luke]]

Based on bug 675015 comment 33, I was excited to try out news.google.com with a nightly.  Unfortunately, it feels decidedly worse.  Again, this is with a MBP trackpad and it makes news.google *extremely* jerky.

Comment 5

[Timothy Nikkel (:tnikkel)]

Enabling smooth scrolling by default would probably make anything that didn't already scroll quickly and cleanly worse.

Comment 6

[Timothy Nikkel (:tnikkel)]

I tested this on my Linux machine as well as a 2+ year old netbook running Windows 7 and the scrolling didn't seem too bad. It seems like this problem might be more specific.

I tested on a Macbook Pro too. Scrolling was smooth, except when you are very near the top and the sidebar on the left is making its transition from being (effectively) fixed positioned to scrolling with the rest of the page.

Comment 7

[Timothy Nikkel (:tnikkel)]

Is it choppy for you over the whole page or just near the top?

Comment 8

[Luke Wagner [:luke]]

just near the top

Comment 9

[Luke Wagner [:luke]]

This seems to have gotten a lot better recently.  Not sure what the fix is, perhaps bug 675015.