Xcode capture and Unity profiler reports different sizes for same texture.

I have been researching texture memory sizes on iOS(iPhone SE)
and I noticed that display sizes of textures are different on Xcode memory capture and unity memory profiler on same device.

For more research, I created a simple project which contains 4 textures, each format are PVRTC RGBA or RGB.
The first attached image is Xcode memory capture in which a texture `t4' is 128 KB,
but the second attached image is unity memory profiler in which a texture `t4' is 11.0 KB.
The `t4' difference does not look so small. What the causes of this difference?





Unity version is 2019.4.17f1. Xcode version is 12.5.

There are many same cases in our production project, so it makes difficult to estimate total texture memory sizes.

 

Thanks your rapidly answer.

Is the Xcode bug only for the case that small textures that are able to pack into 128 KB?
For my another analysis, a texture which is 512x512 pixels of ASTC 6x6 LDR format is reported 115.9 KB by Unity Profiler but 144 KB by Xcode, and it looks that the difference is not only from 128 KB packing of small textures.

For our product, total memory consumption reported by Unity Profiler is far less than 1 GB (800 GB) but over 1.3 GB by Xcode (the application crashes by memory usage). so Xcode looks reporting more accurately than Unity Profiler about memory.

 

Thanks for clear answers.

I'll check another factors you mentions.

I'll be careful if check individual texture sizes on iOS, thank you.

 

1. Significant difference between Xcode and Unity Profiler on crash.

For inspecting memory usage on crash timing, I created a simple application that creates 512x512 texture of 4 different formats every frame.
On iPhoneSE(Memory 3 GB) Xcode and Unity Profiler reports as followings on crash:

- Xcode (instruments): 2 GB
- Uniry Profiler: 1.13 GB

They are not small difference. Application creates textures and does no any other significant task, so this difference looks not to be from memory manager or packing size difference.
All textures are created by code

Code (CSharp):

1. new Texture2D()

so readable object looks to be one of causes of difference between Xcode and Unity Profiler.







2. Unity Profiler reporting inconsistently case.

In the case that another test application which creates Meshes instead of textures, Unity profiler reports odd summary in which Used Total memory is 1.03 GB but Meshes is 1.86 GB (greater than Used Total).



In both cases, Unity version is 2019.4.17f1 and Xcode version is 12.5.

 

Sorry for the delay.

Using Unity 2019.4.28f1 and Xcode 12.5.1, I checked cases where a test program creates a large number of textures and meshes.

• For textures, there was not much difference between Instruments and Unity Profiler.
• For meshes, the difference between Instruments and Unity Profiler was large. Also, Unity Profiler's report was wrong in that the memory size of the mesh was larger than the overall memory size.

The attached table shows the results.
The first row is the result of the texture test and the second row is the result of the mesh test.
The first three columns are the OSX Instruments results, and the remaining columns are the Unity Profiler results.
For the mesh test, Unity Profiler may be wrong in the following ways

• The total memory size of 349.7 MB is too far away from Instruments' 1.21 GiB.
• The size of "Meshes" is larger than "Used Total" and "Reserved Total".