Ubuntu
firefox package

Bug #125970
Comment #197

Comment 197 for bug 125970

Revision history for this message

In Mozilla Bugzilla #201307, Unknown W. Brackets (unknownbrackets) wrote on 2008-05-23:

#197

(In reply to comment #122)
> To those who comment(ed) and/or complain(ed) about this bug:
>
> 1- How many of you have smooth scrolling on?
>
> 2- "dead slow", "horrible", "unbearable", etc.. are very subjective adjectives
> which do not give any kind of accurate measurement, objective measurement,
> quantifiable data, comparable data like a performance profile comparison.
> 0.3sec could be deadly slow to you while 0.4sec could be just fast enough to
> person_B. We have no idea here. How big is the gap between horribly slow and
> fast enough in milliseconds? We have no clue, no idea, not even an hint. And we
> have to compare (and to assess) all these measurements regarding respective
> hardware, configuration, os, settings, etc... involved.

Your comments are very long and I cannot answer all of the points, but I can answer these.

Let's use for a test case "http://www.tuaw.com/". The following builds of Minefield and Bon Echo will be used for comparison:

Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9pre) Gecko/2008052308 Minefield/3.0pre
Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.15pre) Gecko/20080520 BonEcho/2.0.0.15pre

1. general.smoothScroll greatly aggrevates this bug. Since there is UI to turn this on, let's test with it enabled in both Bon Echo and Minefield, please. (note that the problem occurs with it off.)

2. Let us measure how long it takes to scroll to the bottom of this same page in Minefield and Bon Echo. I'm using a not-as-modest AMD 64 X2 3800+ w/2.0 gig of ram, a GeForce 7600 GT at 1280x1024, and XP SP2. We will preform this test by consistently scrolling the mousewheel. I'm timing using my iPhone manually.

Minefield (smoothScroll OFF): 00:08.2
Minefield (smoothScroll ON): 00:14.0
BonEcho (smoothScroll OFF): 00:07.1
BonEcho (smoothScroll ON): 00:07.2

However, Minefield in both cases gets a lot of shearing (a very distinct and definable phenonemon), whereas BonEcho is fine.

Now, this is not a reduced testcase as you say. Good point. Let's make it one. Go ahead and install Firebug in both browsers. For best results, use the same version of Firebug (1.1 or 1.2).

Open Firebug on the website, click "HTML", and then on "<body>". On the right, select the "Style" tab. Look for "background:", and click on it.

Change the value from:
#477CBD url(http://www.blogsmithmedia.com/www.tuaw.com/media/tuaw-bg.jpg) no-repeat fixed 50% 0pt

To:
#477CBD url(http://www.blogsmithmedia.com/www.tuaw.com/media/tuaw-bg.jpg) no-repeat scroll 50% 0pt

This removes the "fixed" scrolling being discussed here. Now, run the above tests again. You will notice a difference.

I imagine this may have to do with possible any of the following factors:
A. Screen resolution/browser size.
B. Length of page and number of elements overlaying background (most likely just height of elements.)
C. Size of background image (width/height.)
D. Positioning of the background image.

This is clearly a regression from Bon Echo (which had no problems here.)

-[Unknown]

(In reply to comment #122)
> To those who comment(ed) and/or complain(ed) about this bug:
> 
> 1- How many of you have smooth scrolling on?
> 
> 2- "dead slow", "horrible", "unbearable", etc.. are very subjective adjectives
> which do not give any kind of accurate measurement, objective measurement,
> quantifiable data, comparable data like a performance profile comparison.
> 0.3sec could be deadly slow to you while 0.4sec could be just fast enough to
> person_B. We have no idea here. How big is the gap between horribly slow and
> fast enough in milliseconds? We have no clue, no idea, not even an hint. And we
> have to compare (and to assess) all these measurements regarding respective
> hardware, configuration, os, settings, etc... involved.

Your comments are very long and I cannot answer all of the points, but I can answer these.

Let's use for a test case "http://www.tuaw.com/".  The following builds of Minefield and Bon Echo will be used for comparison:

Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9pre) Gecko/2008052308 Minefield/3.0pre
Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.15pre) Gecko/20080520 BonEcho/2.0.0.15pre

1. general.smoothScroll greatly aggrevates this bug.  Since there is UI to turn this on, let's test with it enabled in both Bon Echo and Minefield, please. (note that the problem occurs with it off.)

2. Let us measure how long it takes to scroll to the bottom of this same page in Minefield and Bon Echo.  I'm using a not-as-modest AMD 64 X2 3800+ w/2.0 gig of ram, a GeForce 7600 GT at 1280x1024, and XP SP2.  We will preform this test by consistently scrolling the mousewheel.  I'm timing using my iPhone manually.

Minefield (smoothScroll OFF): 00:08.2
Minefield (smoothScroll ON): 00:14.0
BonEcho (smoothScroll OFF): 00:07.1
BonEcho (smoothScroll ON): 00:07.2

However, Minefield in both cases gets a lot of shearing (a very distinct and definable phenonemon), whereas BonEcho is fine.

Now, this is not a reduced testcase as you say.  Good point.  Let's make it one.  Go ahead and install Firebug in both browsers.  For best results, use the same version of Firebug (1.1 or 1.2).

Open Firebug on the website, click "HTML", and then on "<body>".  On the right, select the "Style" tab.  Look for "background:", and click on it.