Unity Issue Tracker - Semaphore.WaitForSignal under Canvas.BuildBatch causes a slow editor in Play mode

Fixed in 2020.1.X

Fixed in 2018.4.X, 2019.3.X

Votes

41

Found in

2018.4

2019.2.0a1

2019.2.1f1

2019.3.0a1

2020.1.0a1

Issue ID

1178300

Regression

Yes

Semaphore.WaitForSignal under Canvas.BuildBatch causes a slow editor in Play mode

Visual Effects - Legacy

Aug 21, 2019

Steps to reproduce:
1. Open the attached project "Temp Project" from the ownCloud link
2. Open "Main Scene"
3. Turn on the Profiler window
4. Enter Play mode
5. Notice the Spikes from Semaphore.WaitForSignal

Expected results: Semaphore.WaitForSignal does not cause spikes in the Profiler window and making Editor slow
Actual results: Semaphore.WaitForSignal causes spikes in the Profiler window and makes Editor slow

Reproducible with: 2019.2.3f1, 2019.3.0b1, 2020.1.0a1

Note: 2019.1 breaks the project and its packages

richardkettlewell

Oct 16, 2019

We are working on a fix for this.

Comments (39)

WheresMommy

Mar 25, 2020 16:46

Well, not fixed at all obviously. 2019.3.4f1
unity_2L-MlLDX1uzHPg

Mar 24, 2020 15:35

Not fixed, 2019.3.6f1.
Batuhan13

Mar 12, 2020 09:29

I am still having this issue in universal render pipeline in my android build it is lagging extremly
shaneK001

Mar 11, 2020 14:13

Not fixed, 2019.3.3f1.
Ilturco

Mar 05, 2020 22:57

I've the same problem in the 2019.2.16.f1 but I "solved" .In my case, I see this fps was down exceptionally when the camera point in the direction of "DontDestroyOnLoad". I took all my scene objects and positioned in y: -1000. Now the DontDestroyOnLoad spawn in top of my scene and the problem are vanished.
BigRookGames

Feb 12, 2020 00:56

experiencing this on 2019.3.0f6
Anil5554u

Feb 09, 2020 21:49

Same issue on 2019.3.0f5
Cec

Jan 16, 2020 10:06

Still not fiixed in 2019.3.0f5
Liviuss

Jan 13, 2020 20:51

I confirm, it's not fixed in 2019.3.0f3.
Rodolfo-Rubens

Dec 27, 2019 17:55

Not fixed in 2019.3.0f3.