Mark chunks that are blocking main thread for world generation as urgent
Implements a general priority system so that chunks that are sorted in
the generator queues can prioritize certain chunks over another.
Urgent chunks will jump to the front of the line, ensuring that a
sync chunk load on an ungenerated chunk does not lag the server for
a long period of time if the servers generator queues are filled with
lots of chunks already.
This massively reduces the lag spikes from sync chunk gens.
Then we further prioritize loading order so nearby chunks have higher
priority than distant chunks, reducing the pressure a high no tick
view distance holds on you.
Chunks in front of the player have higher priority, to help with
fast traveling players keep up with their movement.
This commit also improves single core cpu scenarios in that we will
now automatically disable Async Chunks as well as Minecrafts thread
pool.
It is never recommended to use async chunks on a single CPU as context
switching will be slower than just running it all on main.
This also bumps the number of server worker threads by default too.
Mojang does not utilize the workers in an effecient manner, resulting
in them using barely any sustained CPU.
So give it more workers so more chunks can be processed concurrently
This change also improves urgent chunk loading, so players flying into
unloaded chunks will hurt a little bit less (but still hurt)
Ping #3395#3363 (Not marking as closed, we need to make prevent moving work)
This commit doesn't do much on its own, but adds a new Java Cleaner API
that lets us hook into Garbage Collector events to reclaim pooled objects and
return them to the pool.
Adds framework for Network Packets to know when a packet has finished dispatching
to get an idea when a packet is done sending to players.
Rewrites PooledObjects impl to properly respect max pool size and remove
almost all risk of contention.
Bumps the Paper Async Task Queue to use 2 threads, and properly shuts it down on shutdown.
Now tracks the full startup time for "Done" message at end, as apparently
Vanillas was done in a place that skipped tracking a lot of code too.
This fixes an issue with ViaVersion
Will now run those tasks just before we print "Done" so that startup
time is appropriately accounted for a plugin, as well as will no longer
trip the watchdog on startup.
Any plugin that tries to bypass this is just going to then trip watchdog
on Spigot too, so don't you dare.
Stop trying to cheat the delay your plugin added to startup time.
This isn't a behavior change because the first thing the tick does....
was run these tasks....
So it's just moving it slightly a few lines to be before a watchdog tick and
to account for it in "Done" time.
Fixes#3294
