Hybrid ECS performance test

Run the PlayMode Test to get result in the test log. You must run one by one as I didn't write a proper cleanup between tests. Inspired by this thread.

• A : 250000 game objects with Update().
• B : Manager game object looping 250000 times in one frame to call Update() equivalent.
• C : One ECS system iterate on 250000 entities that was generated from ConvertToEntity with inject mode, and modify values directly to the MonoBehaviour reference like in Update() with Entities.ForEach. The modified values reflected on the GameObject's inspector on the scene. No Burst, no leak detection.
• D : Like C but with a little more work. Added a dedicated IComponentData data storage on conversion for parallel calculation. Apply the calculated value by a copy. Burst on, no safety checks, in editor. No leak detection.
• E : Removed the copy back step from D.

Results

All tests run on MacBook Pro Early 2015 in editor. All units in milliseconds.

• A : Median:88.87 Min:83.32 Max:657.38 Avg:113.88 Std:77.03 Zeroes:0 SampleCount: 100 Sum: 11388.47
• B : Median:21.48 Min:18.86 Max:48.13 Avg:23.81 Std:6.50 Zeroes:0 SampleCount: 100 Sum: 2380.65
• C : Median:27.93 Min:23.71 Max:29.69 Avg:27.38 Std:1.46 Zeroes:0 SampleCount: 100 Sum: 2738.49
• D : Median:24.09 Min:23.31 Max:40.47 Avg:25.19 Std:2.54 Zeroes:0 SampleCount: 100 Sum: 2518.88
• E : Median:7.95 Min:6.32 Max:11.36 Avg:8.04 Std:0.57 Zeroes:0 SampleCount: 100 Sum: 804.17

Evaluation

• Update() is expensive.
• There is a cost on using the query to assemble native array for ForEach from large amount of entities. Otherwise C must be around the same as B, and D should be a bit faster than B.
• You better design for a one-way hybrid approach. Let GameObject use the calculated result stored in ECS via EntityManager, instead of expensive setting back value to MonoBehaviour that is not as cache friendly.