iPhone build w/ wildly different performance on same device

Unity Engine
,
1

Working on a test scene, am seeing widely disparate performance issues on the same build, depending on when it is launched somehow…

The sample scene has a basic consistent physics interaction; nothing is spawned or Instantiated to explain the inconsistency.

When it does not run well (for some yet unknown reason):

iPhone Unity internal profiler stats:
cpu-player>    min: 273.9   max: 311.8   avg: 280.4
cpu-ogles-drv> min:  4.3   max:  6.8   avg:  5.0
cpu-present>   min:  1.8   max:  4.7   avg:  2.3
frametime>     min: 284.2   max: 317.1   avg: 295.5
draw-call #>   min: 11   max: 15   avg: 11
tris #>        min: 4878   max: 5058   avg: 4893
verts #>       min: 3377   max: 3737   avg: 3408
player-detail> physx: 18.7 animation:  0.1 skinning:  0.0 render:  5.4 fixed-update-count: 14 .. 15
mono-scripts>  update: 232.8   fixedUpdate: 19.8 coroutines:  1.2 
mono-memory>   used heap: 1785856 allocated heap: 2076672

Same build (no changes in code, just relaunching), when it runs well (every 4-7 launches):

iPhone Unity internal profiler stats:
cpu-player>    min: 15.8   max: 28.6   avg: 20.8
cpu-ogles-drv> min:  6.8   max: 11.4   avg:  8.9
cpu-present>   min:  1.5   max:  5.9   avg:  2.1
frametime>     min: 31.2   max: 46.5   avg: 38.1
draw-call #>   min: 13   max: 15   avg: 13
tris #>        min: 4914   max: 4950   avg: 4929
verts #>       min: 3449   max: 3521   avg: 3479
player-detail> physx:  3.7 animation:  0.0 skinning:  0.0 render:  7.9 fixed-update-count: 1 .. 3
mono-scripts>  update:  4.3   fixedUpdate:  3.4 coroutines:  0.5 
mono-memory>   used heap: 966656 allocated heap: 1159168

Note the huge drop in ‘mono-scripts’ cycles; this is the same build, simply re-launched run, each time with no user interaction no rebuild between launches.

This disparately occurs whether the build is launched from XCode or from the device itself. Rebooting the device doesn’t seem to affect it in any reliable way; runs well once, then doesn’t run well for a while, then does again.

Imagine is due to some memory / garbage-collection issue. Anyone have any thoughts on this? More importantly, how to mitigate the issue? :slight_smile:

2

well, there are known mem leaks especially in the physics part. there is a beta available without those leaks, you’ll have to ask the developers.

slowdowns on iphone could have several reasons:

debugger seems sometimes to slow down, quit and restart from device for running without debugger

physics engine uses broadphase detection, meaning, that physics objects that are ‘sleeping’ and are out of the screen are not calculated → the more physics objects active, the more to calculate. e.g. if a box drops down to the ground and stays there, it gets ‘sleeping’ until it is hit by something

3

on the launches that are slow, it is slow prior to any collisions; I thought the leak was related to collisions (though am unsure).

If I wasn’t clear in the OP; it doesn’t matter whether I’m debugging or not. Also, rebooting has no reliable affect; still launches sometimes fast, sometimes slow.

The scene has a few kinematic box colliders, and the only non-kinematic physics object makes no collisions prior to the slow down.

The hunt continues! :slight_smile:

4

Submit your app as a bug, post your bug ID here (or PM it to me). I’ll take a look once I have some time.