Huge chunk update stutter when using lots of furniture, MC 1.18.2-latest or more affected, cause and fix included.
Corosauce opened this issue ยท 1 comments
Bug Description
isOptifineLoaded() lacks important class lookup caching, resulting in huge cpu cost when lots of furniture blocks are used:
goes back as far as at least 1.18.2
issue demo 1 100 chairs:
http://share.coros.us/files/pfm_1.mp4
issue demo 2, 300 chairs:
http://share.coros.us/files/pfm_2.mp4
relevant spark profile: https://spark.lucko.me/RyswOA1kw8
piece of interest in the spark profile showing the cpu cost, almost an entire second spent in isOptifineLoaded() during a 18 second profile:
The issue becomes way more obvious when you combine things like Deceased Craft modpack, the biolab uses a lot of this mods furniture, and if you are doing things like holding an offhand torch, its updating a light source near you twice a second, resulting in huge stutters, or anything that does lots of chunk updates.
FIX:
Super easy, just cache the result of Class.forName("net.optifine.shaders.Shaders"), for example you could, in a static block, look up the class and save it in a field, then from there if the field is null, its not installed
eg:
cached lookup: https://github.com/Corosauce/WATUT/blob/1.21.0/src/main/java/com/corosus/watut/client/screen/RenderHelper.java#L54
using the cached lookup: https://github.com/Corosauce/WATUT/blob/1.21.0/src/main/java/com/corosus/watut/client/screen/RenderHelper.java#L117-L120
Reproduction Steps
- Align yourself at the start of a chunk border, eg 0 0
- run: /fill ~ ~ ~ ~16 ~0 ~16 pfm:acacia_chair
- place blocks in that chunk
- witness frame stutters
- place more to see worse and worse frame stutters
Log File
No relevant log file
