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Lag and performance

How to check lag, how far you can see, what the TNT budget does and what lag means for the rules.

Lag is the one thing the server fights. It is fixed in the server. Players are not punished for it.

Check the server

/tps (alias /lag) shows the tick rate and tick time. The number is true.
The tab list shows TPS, MSPT, players online, uptime, world size and your ping. It refreshes every 2 seconds.

/lagreport

/lagreport (alias /lagr) shows what costs server time right now, split by cause:

base load
redstone, pistons and dispensers
explosions and primed TNT
new chunks and loaded chunks
items, mobs, falling blocks, minecarts and boats, and other entities
block entities
player upkeep
an "unexplained" line

It covers the last 10 minutes. It also shows how well the numbers fit, and how uncertain they are.

It never names a player, a place or a dimension.
It needs 5 minutes of data after a restart.
The text is rebuilt every 5 minutes, however often you run it.
When fewer than 5 players were online on average, it only shows the average tick.

/lagreport costs shows the learned cost of each event or entity.

Smooth sight

The view distance is 8 chunks while you move. Stand still for 3 seconds and it grows by one chunk a second, up to 16. Move more than 2 chunks from that spot, or go faster than a sprint, and it drops back to 8 at once.

Your game never reloads every chunk when this happens. The far chunks come and go one ring at a time.
It only grows over land that already exists, so standing still never makes the server generate new land.
Small moves keep it: building, fighting in place or a short pearl.
Your own render distance still applies. Set it to 16 or more to see the whole range.
It pauses for everyone when the server is busy, and at most 10 players can be above 8 at once.
If you chose a width with /trailwidth, it leaves you alone.
The fog in your game sits at 16 chunks. At 8 you can see the edge of the loaded land with no fog in front of it.

/trailwidth

/trailwidth shows your trail width. /trailwidth <4-7> lowers your view distance, and smooth sight leaves you alone while it is set. You see less, and you leave a thinner chunk trail. You can change it once every 10 seconds, and it resets when you log out. /trailwidth off goes back to the default.

The TNT budget

Huge TNT chains used to drop the server to a low tick rate. The server now spreads chain explosions out in time.

A small chain goes off exactly as in vanilla.
A big chain takes longer. A 2,700 TNT field takes about 45 to 65 seconds.
Every lit TNT still explodes, only later. Nothing is lost.
The number of chain explosions per tick drops by half when ticks get slow, and rises again when they are fast.
If too much TNT is already waiting, newly reached TNT stays a block. The next blast sets it off. If a chain stops that way, the server re-lights it about 2 seconds after things go quiet.
Players within 64 blocks see a note when a chain is slowed.

Never changed:

TNT lit by hand, redstone, fire, burning arrows or a dispenser
TNT minecarts
TNT cannons

These keep exact vanilla timing. End crystals, beds and respawn anchors are never touched.

What lag means for the rules

The only rule is not to crash or lag the server on purpose. See Rules.
Even that is not a ban reason. Nobody is banned, muted or kicked for lag.
When something causes lag, 6d63 changes the mechanic. The player is left alone.
Each fix of that kind is written in 6d63's public log, with the date and what changed.

Hosting

The server is in the US West, for low ping on the West Coast. The tab list shows your own ping.