449046 - Hovering over links in large list is slow (with font-variant: small-caps;)

Status: VERIFIED FIXED

(Core :: Layout, defect, P3)

Description

[Boldizsar Palotas]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 6.0; hu; rv:1.9.0.1) Gecko/2008070208 Firefox/3.0.1
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 6.0; hu; rv:1.9.0.1) Gecko/2008070208 Firefox/3.0.1

Hovering over links on the right-most column in http://bp.underground.hu/browse-list.html causes the link styles change to :hover very slowly.
Notice that the first two columns work properly. This might be because the links in the third column are:
    li {display:inline}
and/or styled the same (no different font size like in the 2nd col.)
It is reported (Hungarian: http://kispad.hu/torokgeek/200808/egy-firefox-teljesitmenybug-es-workaroundja.html?&) that bug exists an all platforms but need confirmation.
On Vista (Gecko/2008070208 Firefox/3.0.1) it also causes slightly higher CPU usage than hovering over links in the other columns.

Reproducible: Always

Steps to Reproduce:
1. Create a html page with lots of link in separate inline list items.
2. Hover over it.
Actual Results:  
Link hover styla update is slow.

Expected Results:  
No hover delay.

Comment 1

[Tobias Fischer]

I can confirm this using:
Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.1a2pre) Gecko/2008080400 Mnenhy/0.7.5.20005 SeaMonkey/2.0a1pre

Also on Windows XP hovering Items in the right column eats more CPU than the middle or left one. The Page seems to be valid XHTML 1.0 Transitional, so it should work without Problems. 

It would be helpful, if someone can add an simplified Testcase.

Comment 2

[Pas]

Confirmed on latest nightly. (2008080403)

Comment 3

[Ria Klaassen (not reading all bugmail)]

Works: 2007062012 
Fails: 2007062013

Regression range:
http://bonsai.mozilla.org/cvsquery.cgi?module=PhoenixTinderbox&date=explicit&mindate=2007-06-20+11%3A00&maxdate=2007-06-20+14%3A00
There are two possible culprits in that range; bug 385123 and bug 367177.

Comment 4

[Ria Klaassen (not reading all bugmail)]

Must say that the processor is already working heavily during loading.

Comment 5

[Elmar Ludwig]

This looks similar to bug 416673 (slow performance on zoom + hover, large
number of inline elements that flow into a narrow column).

Like in bug 416673, the column here has a CSS rule "font-variant: small-caps;". Removing this (e.g. via the DOM inspector) seems to bring performance back to normal. In fact, all three columns do have this CSS rule, although only the rightmost one is painfully slow. The middle column shows a bit of lag, but not much.

Comment 6

[Martijn Wargers (dead)]

Attachment: testcase

Branch takes 687ms on the testcase, trunk takes 20518ms.

Why does changing a color of a link take so much cpu? Afaik, changing a color, shouldn't cause a reflow.

Comment 7

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

(In reply to comment #6)
> Branch takes 687ms on the testcase, trunk takes 20518ms.

Which branch?

Comment 8

[philippe (part-time)]

(In reply to comment #6)
> Created an attachment (id=332479) [details]
> testcase

OS X 10.5.4
Gecko 1.8.1 - Fx 2: 415ms
Gecko 1.9.0 - camino: 15491ms
Gecko 1.9.1 - minefield: 20301ms

Comment 9

[Jesse Ruderman]

Dup of bug 430332?  This bug uses "font-variant: small-caps;" and that bug uses "text-transform: uppercase;", but small-caps kinda implies uppercase...

Comment 10

[Martijn Wargers (dead)]

Yes, very likely the same issue.

Comment 11

[Robert O'Callahan (:roc) (email my personal email if necessary)]

Fixed by checkin for bug 430332

Comment 12

[Robert O'Callahan (:roc) (email my personal email if necessary)]

Bug 430332 is fixed on 1.9.1, therefore so is this.

Comment 14

[Aakash Desai [:aakashd]]

verified FIXED on builds:

Trunk: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.1pre) Gecko/20090528 Shiretoko/3.5pre ID:20090528045343


426ms


Shiretoko: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.2a1pre) Gecko/20090526 Minefield/3.6a1pre ID:20090526044156

416ms