71857 - Massive multiple refetch of images on auto-refresh

Status: RESOLVED FIXED

(Core :: Graphics: ImageLib, defect, P2)

Description

[Randell Jesup [:jesup] (needinfo me)]

FreeBSD 4.1 20010312xx

When displaying the attached testcase, it takes a really Long Time to display or
resize.  Note that each cell is:
"<td BGCOLOR="#xxxxxx"><img src="Blank.gif"></td>"
in a "<table width="100%" height="100%" CELLSPACING=0 BORDER=0>"

I suspect a seriously large number of reflows since the images are not
constrained in size, even thought they're all the same image.  This is related
to bug 54542, and may in fact be the same, except that this has blank images and
thus may tickle the reflow code differently.

Also there are semi-random gaps when the table is displayed (in a large window),
but that's another bug probably.

Comment 1

[Randell Jesup [:jesup] (needinfo me)]

Attachment: Testcase - you'll need Blank.gif as well

Comment 2

[Randell Jesup [:jesup] (needinfo me)]

Attachment: Blank gif for testcase

Comment 3

[Randell Jesup [:jesup] (needinfo me)]

Adding original URL - please don't slashdot his site.  Note that the colors
generated each time are different.  Also note we don't support <table
height="100%">

Comment 4

[karnaze (gone)]

Marc, this may be a dup of another bug. Moving to m0.9.

Comment 5

[Marc Attinasi]

In serious need of Quantify, but it sure looks like bug 54542

Comment 6

[Marc Attinasi]

This is a dup of bug 54542 - the same problem but on a smaller scale. Once the 
overwhelming impact of the style sharing degeneration is fixed, if it can be, 
then we may see some differences due to the transparent images in the cells 
(this case will likely be worse, proportionally). But at this time, the problem 
is the same: too many style contexts slowing down style sharing.

*** This bug has been marked as a duplicate of 54542 ***

Comment 7

[Chad Austin]

Verifications.  Tests (if necessary) were done with 2001052504 on Windows 2000.

Please forgive the spam.

Comment 8

[John Morrison]

Reopening. This loads fine on the initial load (in fact, it's not that slow
even before the pending style system changes). But there is a 'Refresh: 60'
header and when that reload occurs it becomes very slow. This something 
to do with HTTP and/or cache. I'm looking into this some more and will post
further (and get this out of attinasi's hands, since this isn't style, as 
far as I can see). 

Comment 9

[John Morrison]

So, the document is a 25x40 cell table, with each TD being something
like this '<TD BGCOLOR="#7f986c"><IMG SRC="Blank.gif"></TD>'.

When the document is initially loaded, the top-level document and one copy 
of 'Blank.gif' are fetched from the server. The page is layed out fairly 
quickly, about 2-3s on a 500MHz/128MB system (not real fast, but not 
pathologically slow). 

But, when the 'Refresh: 60' triggers the reload, we do one unconditional 
GET for the top-level document, and follow that up with (oops!) 1000 additional 
unconditional GETs of the same 1px GIF that is contained in every table
cell. That's not good. (I expect the "random gaps" that appear while the 
table is layed out are just reflecting the asynch fetch of each redundant 
copy).

Clearing the mozilla0.9 milestone that was set (since that has passed), and
adding mozilla0.9.2 kw, and after flipping a coin, giving to pavlov. 

It would be good to at least determine the scope of this problem (i.e., is it 
only for some narrow set of conditions, or is something more fundamentally 
wrong). Note: I tried this in a number of old builds on win2k, and I could see 
this "load 1000" in builds back to 4/18, but not in a build of 4/11 or 4/13.

[I'm probably guilty of morphing this bug from it's original intent. Apologies]

Comment 10

[Stuart Parmenter]

this is prolly my validate always thing

Comment 11

[benc]

If this is an imagelib thing, I'd like to move it out.

Comment 12

[Randell Jesup [:jesup] (needinfo me)]

Probably not an imaglib thing - note that it's assigned to http.

Comment 13

[benc]

->imagelib, since pav has it.

Comment 14

[Blake Ross]

Doesn't look like this is getting fixed before the freeze tomorrow night.
Pushing out a milestone.  Please correct if I'm mistaken.

Comment 15

[Randell Jesup [:jesup] (needinfo me)]

Reverified with mozilla 2001083103 (I'll check with a more recent build soon). 
We're still massively refetching images on automatic reloads.

Comment 16

[Randell Jesup [:jesup] (needinfo me)]

Bug still there in 2001092703 - we should give this some attention - it will
affect news sites that auto-reload like CNN.com

Comment 17

[Randell Jesup [:jesup] (needinfo me)]

Changed subject to match jrgm's change of the focus of this bug.  On
auto-refresh, we're fetching the same image (Blank.gif) thousands of times; on
the initial load we fetch it once.

Comment 18

[Stuart Parmenter]

.

Comment 19

[Michael Sinz]

It seems like the target milestone keeps moving...

Comment 20

[Randell Jesup [:jesup] (needinfo me)]

Pav: Please, please please try to address this bug.  It eats bandwidth....  Lots
of news sites auto-refresh.

Comment 21

[Stuart Parmenter]

fix checked in