[BurstCompile] for all existing jobs #2421
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Nice one! This one should be fine to just merge. I'll aim to get this into next release for general testing. Thank you. :) |
| @@ -219,7 +222,7 @@ public void Execute(int index) | |||
| } | |||
| // Beach texture | |||
| // Adds a little +/- randomness to threshold so beach line isn't too regular | |||
| if (height <= beachElevation + (JobRand.Next(-15000000, 15000000) / 10000000f)) | |||
| if (height <= beachElevation + Unity.Mathematics.Random.CreateFromIndex((uint)index).NextFloat(-1.5f, 1.5f)) | |||
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Hi, could you explain more about this change please? The JobRand helper class providing basic thread safe access to system random was the best solution I could find when migrating the original code into Jobs.
Why are you changing it here? Is the helper class not compatible with burst?
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Why are you changing it here? Is the helper class not compatible with burst?
Yes sir. System.Random, being a managed type, is not compatible with Burst so this forced me to look for a substitute.
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Before ending with this particular solution I dig into this and run some tests to figure out how to generate random numbers within an IJobParallelFor job that can run on many cores at once and without a single memory allocation to maintain a seed (like System.Random does, I presume). You can look through these numerical results in my post here although those are not super interesting.
My conclusion was that Random.CreateFromIndex(index) is good enough to generate non-random sequence of numbers.
Hi! This PR is part of #2416 saga.
What
Burst compilation enabled for all existing jobs. That's it, nothing else.
Why
Burst is not a magical wand necessarily. It is powerful when there is a lot of math calculations but it won't fix a memory access-bound code (L2 cache misses).
Results
It sped up these existing jobs by around a factor of 10x and nearly
*halves*my loading time for exteriors (20-40% reduction)5 secondstotal of work (left), after[BurstCompile]:0.4 secondtotal of work (right)