403202 - flex attribute significantly increases tree drawing time

Status: RESOLVED INVALID

(Core :: XUL, defect)

Description

[Sergey Yanovich]

User-Agent:       Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8.1.8) Gecko/20071004 Iceweasel/2.0.0.8 (Debian-2.0.0.8-1)
Build Identifier: 1.9a8

I am not sure whether this is a bug, but behavior is not obvious to me.

My XR app heavily uses trees. The app has a test suite which traverse all views to check their behavior. 'flex' attribute raises test time and causes size-proportional fluctuations in test duration:

The suite operates on 4 trees. Trees have 5 row on average w/out 'flex' and around 20 w/ 'flex'.

Domain logic (no UI) test takes ~ 0.4 sec.

With flex="1":
tree size                test time
~  10 x  50               ~ 2.0 sec
~ 200 x 400               ~ 2.9 sec
~ 500 x 400               ~ 4.3 sec
~ 800 x 400               ~ 5.5 sec

Without flex:
~  10 x  50               ~ 2.0 sec
~ 200 x 400               ~ 2.1 sec
~ 500 x 400               ~ 2.2 sec
~ 800 x 400               ~ 2.3 sec

Reproducible: Always

Steps to Reproduce:
1. Create a peace of chrome with a tree
2. Measure tree drawing time w/ 'flex'.
3. Measure tree drawing time w/out 'flex'.
Actual Results:  
With 'flex' on, drawing time grows significantly with tree size.

Expected Results:  
Drawing time is not sensitive to tree size.

Comment 1

[Wayne Mery (:wsmwk)]

Does this still happen?
If so, can you attach a testcase file?

Comment 2

[Sergey Yanovich]

Sorry, we no longer build against current trunk. I'll REOPEN if see this again.