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Won't Fix

Votes

0

Found in

2021.3.33f1

2022.3.15f1

2023.2.4f1

2023.3.0a18

6000.0.0b11

Issue ID

UUM-58572

Regression

No

[iOS] Background thread runs a few times slower when “application.targetFrameRate“ is set to 30 compared to 29 on some iOS devices

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How to reproduce:
1. Build And Run the attached “project.zip” project on iOS device
2. Observe the logs

Expected result: The logged time is ~0.2s
Actual result: The logged time is ~0.2s for a few seconds and then ~1s

Reproducible with: 2021.3.33f1, 2022.3.15f1, 2023.2.4f1, 2023.3.0a18

Reproduced on:
VLNQA00310 - iPad Pro 12.9", 13.4.1 iOS
VLNQA00382 - iPhone 7, 13.1 iOS

Not reproducible on:
VLNQA00494 - iPhone 14 Pro Max, 16.3.1 iOS
VLNQA00358 - iPhone 12, 14.1 iOS
VLNQA00392 - iPad (9th generation), 15.0 iOS
VLNQA00120, Google Pixel 2 (Pixel 2), Android 8.1.0, CPU: Snapdragon 835 MSM8998, GPU: Adreno (TM) 540
VLNQA00267, Samsung Galaxy S10+ (SM-G975F), Android 12, CPU: Exynos 9 (9820), GPU: Mali-G76
VLNQA00178, Xiaomi Redmi Note 4 (Redmi Note 4), Android 6.0, CPU: MediaTek Helio X20 MT6797M, GPU: Mali-T880
VLNQA00489, Htc 10 (HTC 10), Android 6.0.1, CPU: Snapdragon 820 MSM8996, GPU: Adreno (TM) 530

Notes:
- reproducible with devices with A8x and A10 chips (user’s info)
- not reproducible when “application.targetFrameRate” is set to 29

  1. Resolution Note:

    We could only reproduce this issue on a single device that is dual core. Mobile devices cannot run all their CPU cores at full power for prolonged periods of time, so with Unity running at higher frame rate and another thread running non-stop Operating System starts throttling the CPU and performance of the background thread degrades. Our testing show no signs of Unity actively interfering with other thread, it looks like the OS schedules the background thread for execution less often, so it does less in the same amount of real time as a result.

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