729656 - Animated Personas cause unexpectedly high CPU usage

Status: RESOLVED FIXED

(Toolkit :: Themes, defect)

Description

[Siddhartha Dugar [:sdrocking]]

After installing this persona Firefox constantly uses 40-45% of the CPU.

https://addons.mozilla.org/en-US/firefox/addon/metal-flowers-animated/

Comment 1

[alex_mayorga]

WFM on Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:13.0) Gecko/20120222 Firefox/13.0a1 ID:20120222031223

~20% CPU usage with this persona on 2 windows (4 app tabs and 5 tabs).

Comment 2

[Siddhartha Dugar [:sdrocking]]

What is your CPU usage normally? For me normally CPU remains under 10% but with this persona it starts fluctuating around 40-45%.

Comment 3

[SpeciesX]

Confirm. On my Quad Core CPU 6-14%.

Comment 4

[rob64rock]

Confirmed on Single Core - Pentium 4...

Without any animated personas CPU usage fluctuates between 10-35% on average

With any animated personas CPU usage fluctuates between 35-80% on average, but on occasion it hits 100% CPU usage.

Comment 5

[Loic]

Attachment: ff10vs13_animated_persona.png

I confirm the CPU usage after installing the animated persona you linked. See my capture with FF10 and FF13: default theme -> animated persona -> default theme

Comment 6

[Loic]

Sorry, I forgot my config:
Intel Core i5-2410M 2.30GHz

Comment 7

[alex_mayorga]

(In reply to alex_mayorga from comment #1)
> WFM on Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:13.0) Gecko/20120222
> Firefox/13.0a1 ID:20120222031223
> 
> ~20% CPU usage with this persona on 2 windows (4 app tabs and 5 tabs).

I'll take that back, normally Nightly uses 2% CPU so this is a 10 fold increase.

Intel Core i5-2540M 2.60GHz

Confirming.

Comment 8

[Siddhartha Dugar [:sdrocking]]

Thanks for finally confirming this. This is a featured persona with ~25K ADUs. I wonder why no one reported this before. And there are users who would've blamed Firefox instead.

Comment 9

[(dormant account)]

Animated personas are a terrible idea. Going to block this on fixing non-animated personas(and whatever redesign that requires) before we proceed here.

Comment 10

[Justin Dolske [:Dolske]]

It's already possible to stop animations (eg, press ESC in a page with an animated gif), I'd suspect it should be fairly simple to have chrome just immediately do that whenever applying a persona?

There's probably still some memory overhead for the animation frames, not sure how smart we are with that (afaik we still do work with gifs to avoid giant decoded buffers hanging around, not sure of APNG gets similar treatment).

Halting animations should be a trivial fix, but I do wonder how much of this is a problem with with images/gfx/invalidation/whatever. There was an old Firefox 4 (3?) bug about the 16x16 APNG throbber eating significant CPU when shown. Given the popularity of sites like http://www.gifbin.com/ and http://gif.tv, I'd worry a bit that animated personas are just 1 instance of a much more general problem.

Comment 11

[Joe Drew (not getting mail)]

(In reply to Justin Dolske [:Dolske] from comment #10)
> There's probably still some memory overhead for the animation frames, not
> sure how smart we are with that (afaik we still do work with gifs to avoid
> giant decoded buffers hanging around, not sure of APNG gets similar
> treatment).

To be clear, we just store the GIF data raw for subsequent frames; we convert it to RGBA for the first frame only.

APNG has no such internal optimization, and as such it has no similar treatment.

Comment 12

[Justin Dolske [:Dolske]]

Oh dear. So, that implies that with 3000x200 Persona headers, each frame is 2.4MB of RGBA data (or a mere 1.8MB if it can end up as just RGB). 1.5x those numbers if the Persona has a similarly-animated 3000x100 footer too.

Yeahhhhhh... We should kill that.

I'm guessing we never discard decoded frames even when the animation is stopped, so we should probably just detect animations and refuse to load them. Probably need a spinoff big to detect and kill these on the server too (to block new uploads, and clear out Personas that would actually no longer work).

Comment 13

[Joe Drew (not getting mail)]

(In reply to Justin Dolske [:Dolske] from comment #12)
> (or a mere 1.8MB if it can end up as just RGB).

It can't.

> I'm guessing we never discard decoded frames even when the animation is
> stopped

We never discard animated images, full stop.

Comment 14

[Max Stepin]

Only the first frame is full-size. Frames that animate butterflies are much smaller and do not require a lot of memory.

It's almost always the case. Hard 300k size limit forces Personas Authors to animate only a small portion of the image.

Comment 15

[Tim Taubert [:ttaubert] (inactive)]

(In reply to Justin Dolske [:Dolske] from comment #12)
> Yeahhhhhh... We should kill that.

That's been done by bug 650968. It would display animated LWTs right after the installation but those would be cropped versions of the first frames after a restart.

> I'm guessing we never discard decoded frames even when the animation is
> stopped, so we should probably just detect animations and refuse to load
> them. Probably need a spinoff big to detect and kill these on the server too
> (to block new uploads, and clear out Personas that would actually no longer
> work).

We still need to do this. We could alternatively take the first frame of existing animated LWTs and convert them to non-animated automatically.

Comment 16

[Max Stepin]

Maybe you should announce somewhere that animated personas are about to be killed.

And ask users for feedback.

Comment 17

[Tim Taubert [:ttaubert] (inactive)]

Fixed by bug 650968.