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Fixed in 2020.1.X
Fixed in 2018.4.X
Votes
2
Found in
2018.3.5f1
2018.4.0f1
2019.1.0a1
2019.1.13f1
2019.3.0a7
2020.1.0a1
Issue ID
1175268
Regression
Yes
Canvas.BuildBatch 50% - 70% CPU spikes when dragging mouse from Unity window to any other OS window
To reproduce:
1. Open "ExtractedScene 2019.1.zip" project
2. Open "reproTryVeryMin.unity" scene
3. Enter Play mode
4. Scroll on the white block on the left
5. Observe Profiler
6. Drag mouse between macOS dock and Unity Editor
Expected: Canvas.BuildBatch CPU usage should be 0.1% - 4%
Actual result: getting 50% - 70% CPU spikes on Canvas.BuildBatch
Reproduced on:
2018.3.5f1 2018.4.0f1 2019.1.14f1 2019.3.0a7 2019.3.0b1 2020.1.0a1
Not reproduced on:
2017.4.32f1 2019.2.3f1 2019.3.0a6 (getting about 0.1% - 0.5% usage)
Notes:
- Reproduction video in edit
- On 2019.3.0a6 getting the same spikes but up to 20%
- 2018.3.2f1 - 2018.3.4f1 getting the same spikes but Canvas.BuildBatch is using 0.1% - 4%
- In 2018.3.0a1 - 2018.3.0f1 constant spikes are appearing but the Profiler window shows only 0.1% - 4% CPU usage in Canvas.BuildBatch (1830a1.png)
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Resolution Note (fix version 2020.1):
Planned backports are shown here: https://issuetracker.unity3d.com/issues/semaphore-dot-waitforsignal-causes-a-slow-editor-when-entering-play-mode