The nibble pooling for NBT Tags was 'semi' leaked from loaded chunks
as we store the NBT Tag of Tile Entities in a Chunk, but don't process
them and remove them until chunk reaches Entity Ticking status....
This caused some phantom references to persist causing high memory use
of these chunks.
So I just got rid of pooling from NBT deserialization and we'll have to
take the hit on memory allocations there because too many cascading concerns
with anyone using NBT Tag Byte Arrays.
Fixes#3431
synchronized arraydeque ends up still being way faster.
Kinda shocked how much that strategy was using, it wasn't really
that complicated... but oh well, this is even simpler and not
seeing blocked threads show up at all in profiling because
the lock is held for such a short amount of time.
also because most uses are on either server thread pool or chunk load pool.
Also optimize the pooling of nibbles to not register Cleaner's
for Light Engine directed usages, as we know we are properly
controlling clean up there, so we don't need to rely on GC.
This will return them to the pool manually, saving a lot of Cleaners.
Closes#3417
Dynmap accessed the raw bytes because it utilized NBT locally, but the
NBTTagcompound was garbage collected while the bytes were still being used.
This will return getBytes() back to being safe, and add a new PoolSafe method
that will prevent the additional allocations for general chunk loading.
Also fixed applyPatches for people with paths in their working directory
if they have mcdev sources built.
Massively reduces memory allocation of 2048 byte buffers by using
an object pool for these.
Uses lots of advanced new capabilities of the Paper codebase :)
Targets 3072 * 8 buffers per 1GB of heap memory up to a max consideration
of 6GB of heap (any more over 6GB won't give more nibble pool)
You can control the 3072 number by setting -DPaper.nibbleBucketSize=2048
Remember this number is * 8 then * heap memory in GB
That is 98304 objects for 4GB of memory, at 2064 bytes roughly, meaning 194MB
You may also control max number of pooled objects directly instead of any
dynamic calculation using -DPaper.maxNibblePoolSize=1024000
While this will use more old generation by a tad bit, allocation rate will drop
significantly, causing less young generation GC's.
This commit has gone through extensive testing for over a day and confident
it no longer has any issues with light corruption.
Aikar
Spottedleaf