When a player triggers a chunk load via walking around or teleporting there
is no need to stop everything and get this chunk on the main thread. The
client is used to having to wait some time for this chunk and the server
doesn't immediately do anything with it except send it to the player. At
the same time chunk loading is the last major source of file IO that still
runs on the main thread.
These two facts make it possible to offload chunks loaded for this reason
to another thread. However, not all parts of chunk loading can happen off
the main thread. For this we use the new AsynchronousExecutor system to
split chunk loading in to three pieces. The first is loading data from
disk, decompressing it, and parsing it in to an NBT structure. The second
piece is creating entities and tile entities in the chunk and adding them
to the world, this is still done on the main thread. The third piece is
informing everyone who requested a chunk load that the load is finished.
For this we register callbacks and then run them on the main thread once
the previous two stages are finished.
There are still cases where a chunk is needed immediately and these will
still trigger chunk loading entirely on the main thread. The most obvious
case is plugins using the API to request a chunk load. We also must load
the chunk immediately when something in the world tries to access it. In
these cases we ignore any possibly pending or in progress chunk loading
that is happening asynchronously as we will have the chunk loaded by the
time they are finished.
The hope is that overall this system will result in less CPU time and
pauses due to blocking file IO on the main thread thus giving more
consistent performance. Testing so far has shown that this also speeds up
chunk loading client side although some of this is likely to be because
we are sending less chunks at once for the client to process.
Thanks for @ammaraskar for help with the implementation of this feature.
CommandMap now contains the functionality for tab completion. This
commit replaces the vanilla implementation and simply delegates it to
the Bukkit API.
This change affects the old chat compatibility layer from an
implementation only standpoint. It does not queue the 'event' to fire,
but rather queues a runnable that allows the calling thread to wait for
execution to finish.
The other effect of this change is that rcon connects now have their
commands queued to be run on next server tick using the same
implementation.
The internal implementation is in org.bukkit.craftbukkit.util.Waitable.
It is very similar to a Future<T> task, but only contains minimal
implementation with object.wait() and object.notify() calls
under the hood of waitable.get() and waitable.run().
PlayerPreLoginEvent now properly implements thread-safe event execution
by queuing the events similar to chat and rcon. This is still a poor way
albeit proper way to implement thread-safety; PlayerPreLoginEvent will
stay deprecated.
The new setting is located at "ticks-per.autosave". By changing this
value, it affects how often a full save is automatically executed,
measured in ticks.
This value is defaulting to 0 (off) because we believe that the vast
majority of servers already have a third-party solution to automatically
saving the server at set intervals. Having the built in auto-save disabled
by default ensures that we are not saving things twice; doing so leads to
absolutely no benefits, but results in detrimental and noticeable
unnecessary performance decrease.
For servers that do not use an automated external script to perform saves,
this setting can be turned on by setting the value higher than 0, with 900
being the value used in vanilla.
- Hardcore requires a newly generated world
- You will be banned if you die in a hardcore world
- You will NOT be banned if you die in a non-vanilla world
- Your "heart container" will not change without logging back in. (Vanilla bug)
Added two utility collections for use with PlayerChatEvents allowing lazier
initialization of events and less need to synchronize against the player
list.
Provided a hidden queue system for similar logic to pre-1.3 chat. When a
plugin is listening for the deprecated PlayerChatEvent, all chat will be
delayed to be mirror executed from the main thread. All developers are
encouraged to immediately update to the developmental Bukkit chat API as a
minimum transition for server stability.
Additionally, changes were required to bring thread-safety to the flow
logic. CopyOnWriteArrayList is the only viable means to produce thread
safety with minimal diff; using a sane pre-implemented collection would
require reworking of sections of NMS logic.
As a minor change, implemented expected functionality for
PlayerCommandPreProcessEvent. Setting the player should now change the
player executing the command.
Both the CB 1.3.1 code, and vanilla 1.3.1 code, have modified the
behavior of entity tick processing in a way that can lead to disabling
of entity cleanup. Specifically, the tickEntities() call in n.m.s.World,
which processes both the entity cleanup (removing from the world entity
list) and tile entity tick processing (furnaces and such) does not get
called by n.m.s.MinecraftServer's q() method (which drives tick
processing calls in general) when no players are on the given world.
This causes a serious memory leak when automation processes, like dynmap
mapping, load and unload chunks - as entities on unloaded chunks are
only cleaned up during entity tick processing. It also will cause issues
with any mods that use persistent chunk loading (that is, keeping chunks
loaded so that tile entities will continue being processed), since such
processing will no longer function without at least one player on the
given world.
In any case, the tickEntities() call should be called in the same
fashion as under 1.2.x (each tick, independent of player population, as
opposed to being suspended indefinitely when no players are on the given
world). The specific memory leak observed, with removing the unloaded
entites from the world, requires this call be made regularly (or, at
least, whenever the entity unload queue (world.g) is not empty.
Closes GH-832
Added newlines at the end of files
Fixed improper line endings on some files
Matched start - end comments
Added some missing comments for diffs
Fixed syntax on some spots
Minimized some diff
Removed some no longer used files
Added comment on some required files with no changes
Fixed imports of items used once
Added imports for items used more than once
We know these updates (can) break plugins bypassing Bukkit. They are needed for
smooth updates however. There will be another one right before before 1.1-R1.
