this should provide a pretty good across-the-board performance
improvement for the entire server, as it's very common for code
to check if (isLoaded(x, z)) { then do something on that chunk }
Previously, containsKey would not read or set the last access cache
By making it do get() != null, we gain the benefits of last access
and also improves thread safey for async isLoaded checks
This exact usage scenario is used in Entity movement, so that alone
saves us up to 5%~ of CPU time for Entity movement.
Mojang was not checking that the chunk did not overwrite, or
was successfully removed.
We're seeing odd reports in #1561 that indicates issues around
this are having problems.
Upstream has released updates that appears to apply and compile correctly.
This update has not been tested by PaperMC and as with ANY update, please do your own testing
Bukkit Changes:
39ce5d3a SPIGOT-4399: ItemMeta.equals broken with AttributeModifiers
CraftBukkit Changes:
1cf8b5dc SPIGOT-4400: Populators running on existing chunks
116cb9a1 SPIGOT-4399: Add attribute modifier equality test
5ee1c18a SPIGOT-4398: Set ASM7_EXPERIMENTAL flag
Upstream has released updates that appears to apply and compile correctly.
This update has not been tested by PaperMC and as with ANY update, please do your own testing
CraftBukkit Changes:
7033f180 Hoist out synchronisation from ChunkRegionLoader
Spigot Changes:
500ff5d4 Rebuild patches
Additional Paper changes:
Fixed Versioned World Folders to not synchronize on ChunkRegionLoader
Optimized Save Queue even more to use a Long2ObjectOpenHashmap for save map
Add World#getXIfLoaded to IWorldReader to expose it to more places
Also fixes some bugs in ours
Ultimately they both are near the same, but ours is behind the synchronized gate.
Mojangs is mixed behind 2 different synchronization contexts (chunks can lock 2 different objects)
Mojang also blindly unsets the ref on any chunk unload, not just if its the one being pointed to.
CraftBukkit removed their implementation that caused this issue,
switching to Mojang's implementation which doesn't appear to share it. I
already removed the important bit in the last upstream merge, this is
just unused and unnecessary now. So we remove it.
getting a loaded chunk is one of the most hottest pieces of code in the game.
Often, getChunkAt is called for the same chunk multiple times in a row, often
from getType();
Optimize this look up by using a Last Access cache.
Aikar
Shane Freeder
Zach Brown