renderMode gpu on iOS -- severe performance degradation in AIR 18?

[Eyal_Katz]

Hi All,|

We just moved to AIR 18 (from AIR 15) in order to meet with Apple's new requirement about 64-bit applications.

We noticed a severe performance degradation (2-3 FPS) on iOS devices when playing a certain animation with a couple of large image files (1000x600).

In the first couple of times the animation playback was smooth, but after a couple of minutes into the game, the animation suddenly starts to lag, until an application-restart is required.

This does not happen on Android devices.

This issue does not occur on AIR 15

Using Scout, we noticed that "Decompressing Images" is responsible for 99% of the frame's time.

We suspect that the GPU is not correctly cleared, and that the runtime is kept endlessly busy swapping images.

We managed to test this by deliberately choking up the GPU on AIR 15 & 18, and indeed in AIR 18 the runtime slowly degrades.

Please advice on what to do, as we can't upgrade our application in the App Store until this issue is resolved.

Thanks

Eyal

[smolho]

Strongly upvoting this post - we also encountered this severe issue while moving our iOS application from AIR15 to AIR18.

After continuously adding and removing large images on screen, the application start to slow down, and Scout shows it's all on "Decompressing Images".

The thing is, that the app never recover from this - I would expect removing all images from screen and then adding just some will improve performance, but there seems to be an overall degredation.

We're just stuck.

We can't publish any iOS applications until this issue will be fixed.

Anyone from Adobe, can you answer on this? this is the community official forum after all...

[tdwivedi]

Hi Eyal Katz,

We have been able to reproduce earlier, and our findings have been similar to what you have mentioned, ie. we were able to see FPS drops in Scout, specially for Decompressing Images. But the issue was happening intermittently, and more importantly, we were not able to see any significant effect on the device's screen. We could see fps drops in between, but as we weren't seeing noticeable effect on the screen So, we were keeping the priority low.

We would love to work on this issue if it is causing performance degradation in the actual application, as you have mentioned.

But we will need some detailed information about the issue.

1. Exact iOS version(s) on which you are facing the issue.

2. What is the effect you are seeing on the screen, can you share a video or a sample app in which similar behavior is reproducible?

3. Which AIR build (15.x.x) you were using earlier (in AIR 15, where it was working fine) and now (in AIR 18, where it is causing performance issue)?

-Tushar,

Adobe AIR Team

[Eyal_Katz]

Hi Tushar,

Thanks for the help, we're in great need for you guys' attention on this... here is my reply to your questions:

1.

We experience this issue in many iOS 8.X versions, for example iOS 8.3 (12F70)

2.

The following video clearly shows how an animation is lagging after playing the game for about 4-5 minutes.

https://dl.dropboxusercontent.com/u/14766452/techs/flash/ios-air-18/video1.mp4

The following videos shows the same animation - with slight lags - after 2-3 minutes of gameplay.

Notice the lags around time 00:03 of the video.

https://dl.dropboxusercontent.com/u/14766452/techs/flash/ios-air-18/video2.mp4

Before that, the very same animation runs smoothly.

On AIR 15, this animation was running smoothly all of the time, even after hours of gameplay.

3.

The same application runs without any issues on AIR 15.0.0, build 356.

The issues reported here were noticed on AIR 18 build 144.

Actually, we also noticed these issues while running our application on AIR 16 and even 17.

*

Can you give us your first impression of what's going on?

We're highly interested in any details regarding this issue as we can't publish our games in iOS until this is resolved, and we want to be able to give our customers and backers some information and time estimations...

Again, thank you very much for the help, and we hope to hear from you soon,

Eyal

[tdwivedi]

Hi Eyal Katz,

We have tried reproducing this issue using few sample applications at our end, but this behavior wasn't replicated. We would like to work closer to the scenario you are working with, to ensure we are able to find the problem sooner. Can you provide a sample AIR project, in which you are able to reproduce this issue?

-Tushar,

Adobe AIR Team

[Eyal_Katz]

Hi Again Tushar,

Below is a link to an IPA you can install and test the application:

https://www.dropbox.com/s/pka4qnyzhmkkyro/slotagram-prod-adhoc.ipa?dl=0

After installing, you will need to play a little while with the game, and after around 4-5 minutes, the performance issue will occur.

I will need you Player Id so I could add you to our "Test Players" to grant you with special features which will make testing much easier.

Thank you ,

Eyal

[Eyal_Katz]

Tushar and the rest of the AIR team,

I request you once more to please try and resolve this issue with us.

You can download our (buggy) application directly from iTunes, play with it for 4-5 minutes and see the performance degradation

https://itunes.apple.com/us/app/slotagram-build-your-slots!/id895742021?mt=8

We noticed that every time the Flash Player has to display big images (which weren't on screen before), it's a 50:50 chance if it'll start to lag and slow down the entire system, as if it's choking up the GPU or something (texture swapping??)

Again, this DOES NOT happen in AIR 15, and only started to show on AIR 18 (maybe the move to 64 bit??)

Apple requires all it's new apps to be 64-bit compatible, and so we're stuck with a malfunctioning version of our application in iOS.

Please reply,

Thank you

Eyal

[tdwivedi]

Hi Eyal Katz,

When I'm trying to start the application, the initial launch screen is being stuck at 96%, and the application isn't getting started ? I tried on various different networks, to make sure it's not due to network restrictions. Can you help with this, so that we may proceed with testing the app.

Moreover, I doubt that just by running the .ipa, we will be able to help you with the issue effectively. We will be needing a sample application (a project) in which you are able to reproduce the issue. It doesn't have to be your actual application's code, just the sample project (code + resources) on which you are able to reproduce the issue.

-Tushar,

Adobe AIR Team

[Eyal_Katz]

Dear Tushar,

I will soon post here a link to a simple project you can compile and run which will demonstrate the issue we're facing.

Stay tuned

Eyal

[Eyal_Katz]

Hi Tushar and the Adobe AIR team,

The reason your app is stuck on 96% is due to a bug we found in AIR 18.0.0.144 and 'ipa-app-store' packaging, in which the app just enters an infinite loop and freezes (on some devices such as iPhone 5 (but not 5s) or iPad 3rd gen)

This bug does not occur on AIR15

See it here:

https://bugbase.adobe.com/index.cfm?event=bug&id=4048131

We managed to overcome this bug and we're submitting our application to Apple again.

In the meanwhile I'm working on a sample application to demonstrate the GPU performance degradation.

For some reason, it's more difficult to reproduce this issue on a sample application, but it's constantly happening on our application (but not when deployed with AIR 15)

Question: Which iOS device did you to see that "96% Freezing" issue?

Eyal

4048131

40481314048131

[tdwivedi]

Hi,

I had tried on iPad 3 (iOS 8.1.3). Thanks for the info, I will also try it on few other devices.

-Tushar

[tdwivedi]

Hi Eyal,

Were you able to get the issue reproduced in a sample project ?

-Tushar

[Eyal_Katz]

Hi Tushar,

Unfortunately, I wasn’t able to reproduce this bug in a sample project… I’m probably missing something about understanding the root cause of it.

I am sure this is an AIR18 Bug, as the exact same application runs smoothly on AIR15.

If you download our game from the App Store, you will notice that the game drops to 1 FPS after a while, and rarely ever recovers back to normal.

You will also notice that this bug is always triggered by a burst addition of dozens of new images on screen (i.e. images that weren’t on stage before). For example a “BIG WIN!” message that suddenly appears on screen, with a couple of Full HD images inside it... or a set of 25 images, 300x300 size, added at once to stage…

What's common here, is that it's always many images that weren't on screen before, added to stage (uploaded to the gpu?) in single frame

This immediately led me to suspect that there’s a bug in renderMode=GPU, probably in the area where it decides which textures to upload or remove from the GPU.

I just can’t think of any other reasons… my test applications tried to do just the same, but something is missing I think, and I’m calling for your help on this…

Here’s a link to Scout recording this bug in action, Navigate to time 09:27 to see the bug

https://dl.dropboxusercontent.com/u/14766452/techs/Scout/AIR18_GPU.flm

You will see that a frame takes 1 second to render, where ~300ms are spent on GC, ~300ms on “Decompressing Images” and ~300ms on “Building edges from DisplayObject”, but maybe you'll see something that I didn't see...

My Questions are:

• Could there be a hidden bug at your side in the area of uploading many images at once to the GPU in renderMode=GPU?
• Could it be related to the 64bit transition made in AIR18? (Again this does not happen in AIR15)
• Do you need anything more from me in order to understand this issue? just ask.
• Although these are just theories, I’m interested in your opinion about them, what do you think Tushar?
• 
  

Thank you very much

Eyal