851413 - Dynamic resizing a single image can eat 2 CPU cores

Status: RESOLVED WORKSFORME

(Core :: Graphics: ImageLib, defect)

Description

[Mayank Bansal]

User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:22.0) Gecko/20130314 Firefox/22.0
Build ID: 20130314030914

Steps to reproduce:

1. Start a fresh profile
2. Go to http://www.tweaktown.com/news/29104/netflix-offering-100-000-in-prizes-to-those-who-can-best-improve-the-cloud/index.html

3. Bring the mouse pointer over the main image.
4. A dynamic pop up of the full size image will appear. As you move the mouse inside the image, the pop-up image will dynamically resize to best fit teh screen.
5. Open Task Manager , and repeat step 3/4.


Actual results:

Firefox is using 2 full CPU cores. So on a Quad core, you get 50% CPU usage.


Expected results:

Lesser CPU use, mayb.
I am not sure if this is a bug, or the intended behavior.  In any case using that much CPU for a single image looks gratuitous.

Comment 1

[Mayank Bansal]

Here is a profile :
http://people.mozilla.com/~bgirard/cleopatra/#report=79e910251720da0ca61a2c3180bd6d4837e77c93

Comment 2

[Josh Matthews [:jdm]]

Profile shows 30% flushing layout, 20% running page JS, 14% painting.

Comment 3

[Mayank Bansal]

the page layout has changed. So the dynamic resize of images is not there.