999187 - [Settings] warm launch on settings averages between 25 FPS after 6 tries

Status: RESOLVED WONTFIX

(Firefox OS Graveyard :: Gaia::Settings, defect, P3)

Description

[Tony Chung [:tchung]]

When launching and closing settings app, the instrumented FPS averages about 25 FPS after about 6 tries.    It should be close to 55-60 (industry)

See screencast: http://youtu.be/-Um62URGZIg

Need to retest on 1.4 and 1.3 as soon as we have available builds there.

order of 6 tries:
1. 44 
2. 29
3. 21
4. 36
5. 16
6. 20

Repro:
1) install 2.0 on Flame nightly.  

Gaia      eb97461e75cd44d20967bc410b5653dff031ef5a
Gecko     https://hg.mozilla.org/mozilla-central/rev/5010b38abf18
BuildID   20140421040204
Version   31.0a1
ro.build.version.incremental=68

2) open and close Settings app a few times.  Watch the instrumented FPS numbers in the upper left hand corner

3) Verify the FPS counter averages around 25 FPS or so.  more hits will give you a tighter average, but nothing like ~55-60 FPS

Expected:
- warm launch of Settings averages about 55-60

ActuaL:
- average around 25 FPS

Comment 1

[Milan Sreckovic [:milan] (needinfo for best results)]

Some additional information:

"The behavior is the same on at least one other device (Tarako) and Tony can verify it on Hamachi and other as well."

"On Tarako we’re running 1.3 so it’s a problem in that release as well.  if we’ve regressed it’s been for a while."

One more question - is this the frame rate when launching (from the description that's what I'm guessing), not when scrolling, right?  If it is launching we're talking about, are you sure the requested animation is producing 60 different frames per second?

Comment 2

[Milan Sreckovic [:milan] (needinfo for best results)]

Just to clarify the comment above.  If we request an animation of five animation frames per second, even on an infinitely fast device we are going to show 5 fps measurement because that's all we *need* to show.  We're smart enough not to refresh each animation frame 12 times, if there are no changes.

Comment 3

[Mason Chang [Inactive] [:mchang]]

Triage: Going with comment 1 and 2 from Milan. If the open animation actually doesn't require that many frames, it means we won't composite. Since we didn't composite new frames, the FPS counter is going to be low because we didn't actually do any work. Notice that the number kind of freezes ~25. Resolving as WONTFIX. Please reopen if needed. Thanks!

Comment 4

[Milan Sreckovic [:milan] (needinfo for best results)]

Somebody from the settings app should confirm what kind of animation we're requesting.

Comment 5

[Faramarz Rashed]

adding andreas to CC since he is keen on following up on these issues.

Comment 6

[Tony Chung [:tchung]]

Tried this again with setting app, this time on a Buri device running 1.4

See screencast: http://youtu.be/aUjMTfTjrxg

runs: 33fps, 24, 33, 33, 40, 33, 37 /7 runs avg = ~33.28

If i'm not recording the results correctly, someone can educate me on what i should be looking for.

Comment 7

[Milan Sreckovic [:milan] (needinfo for best results)]

Looking at FPS is not telling you how fast we're drawing, but how many things we're drawing.  Think of a scenario where you ask for the screen to update once every second. The fps display will show 1fps.  That doesn't mean things are failing, it just means you're not asking for more than one update per second.  I don't know what the settings app is asking for the transition.  If it's asking for 60 updates per second, then this is a performance issue.  If it's asking for 30 updates per second, then this is fine.  If it's asking for "as fast as possible", then this is a performance issue.

Comment 8

[Tony Chung [:tchung]]

(In reply to Milan Sreckovic [:milan] from comment #7)
> Looking at FPS is not telling you how fast we're drawing, but how many
> things we're drawing.  Think of a scenario where you ask for the screen to
> update once every second. The fps display will show 1fps.  That doesn't mean
> things are failing, it just means you're not asking for more than one update
> per second.  I don't know what the settings app is asking for the
> transition.  If it's asking for 60 updates per second, then this is a
> performance issue.  If it's asking for 30 updates per second, then this is
> fine.  If it's asking for "as fast as possible", then this is a performance
> issue.

Great, i'm looking for more guidance here to make sure we're reporting things right.  How can i locate what amount of time the apps are asking for during the update?

Comment 9

[Milan Sreckovic [:milan] (needinfo for best results)]

Somebody from Gaia::Settings should be able to tell us - I don't know who that is.

Comment 10

[Mike Lee [:mlee]]

Hi Evelyn,

Please respond to Milan's comment 7 and comment 9 re: the Settings app's FPS needs. You're listed as the Settings module owner[1] but if another Settings peer will be better able to answer please needinfo them.

Thanks,
Mike

[1] https://wiki.mozilla.org/Modules/FirefoxOS#Settings

Comment 11

[Evelyn Hung]

(In reply to Milan Sreckovic [:milan, travelling, maybe slow to respond] from comment #2)
> Just to clarify the comment above.  If we request an animation of five
> animation frames per second, even on an infinitely fast device we are going
> to show 5 fps measurement because that's all we *need* to show.  We're smart
> enough not to refresh each animation frame 12 times, if there are no changes.

I'm not sure how to calculate frame number of an animation, can you give me a way to measure it?

If we are saying the frame rate when launching without any scrolling, I can only think of a 
|transition: transform .4s ease| *might* be applied that makes the Settings' root panel moving from translateX(+100%) to translateX(0). (Well, I also remembered we optimized here so the animation will be skipped while launching, :arthur, please correct me if I'm wrong.)

Other repaints are mainly caused by subtitle updates which depends on how fast the API returns the requesting information, so I have no idea how to estimate its frame rate. :(

Comment 12

[Arthur Chen [:arthurcc][inactive after 6/30]]

Currently there is no animation used in settings app when it starts. The animation shown in the video is applied in system app. I checked other apps on inari and they have similar performance, too. Sometimes there is no animation at all. The issue may not be specific to settings app.