Performance tuning

Find the setting that matches a symptom, and check the server before you change anything.

This page covers stratum-performance.json, the file that holds the load settings. The keys below are the names inside that file. To change one in game, add the Performance. prefix, for example /stratum set Performance.ChunkSending.MaxChunksPerServerTick 384. Most servers can leave these at their defaults. Start with /stratum timings and /stratum performance. They show where the server spends its time, so you change the setting that matches the problem.

Read the current state

/stratum performance shows which performance features are on and how full their queues are.

/stratum timings shows where tick time goes. Timings are off at startup. To turn them on for the next start:

/stratum set Performance.Timings.EnabledOnStartup true

Restart the server afterwards. While the server runs, /stratum timings start, /stratum timings stop, and /stratum timings reset control the timings.

Chunk sending

When players move or join, the server sends them terrain chunks. Many moving players at once can spike tick time.

Key	Default	Effect
`ChunkSending.MaxChunksPerServerTick`	`384`	Hard cap on chunks sent per server tick
`ChunkSending.FairSchedulingEnabled`	`true`	Spreads sends across players instead of serving one player first
`ChunkSending.AdaptiveUnderOverload`	`true`	Lowers the send rate when the server is under load
`ChunkSending.OverloadTickMs`	`45`	Tick time above which the reduction starts

If players see long load-in times and other players lag during big joins, lower MaxChunksPerServerTick, or reduce join pressure with the settings below.

Join pressure

Key	Default	Effect
`Join.CacheStartupPackets`	`true`	Reuses startup packet payloads for repeated joins
`Join.MaxQueueAdmissionsPerPass`	`2`	Queued clients admitted to the join path per tick pass
`Join.MaxJoinsPerTick`	`3`	Joins handled per tick

Entity ticking

Entity ticking has its own page: Entity tick throttling. Use it when TPS drops with many animals loaded and no players near them.

Pathfinding

Creature pathfinding runs on background workers. The queue can back up under pressure.

Key	Default	Effect
`Pathfinding.Async`	`true`	Runs path requests on background workers
`Pathfinding.MaxQueued`	`512`	Limit on pending path requests
`Pathfinding.PriorityEnabled`	`true`	Serves near-player requests first when the queue passes `PriorityQueueThreshold` (default `64`)
`Pathfinding.DropFarTasksUnderPressure`	`true`	Drops requests farther than `FarTaskDistanceBlocks` (default `160`) when the queue is under pressure
`Pathfinding.MaxTaskAgeMs`	`2000`	Drops tasks older than this many milliseconds

Autosave

Autosave spreads write work across ticks instead of doing it all at once.

Key	Default	Effect
`AutoSave.IncrementalFlushIntervalSeconds`	`10`	Seconds between incremental flushes
`AutoSave.MaxLoadedChunksPerFlush`	`256`	Chunks written per flush
`AutoSave.MaxDelaySeconds`	`120`	Longest a save can wait while chunk pressure is high

If TPS drops every few minutes and the server stalls during a save, lower MaxLoadedChunksPerFlush. Each flush then writes less, and the work spreads over more flushes.

Block ticks

Block ticks (crops, furnaces, growing plants) run on the main thread and add up in a large world.

Key	Default	Effect
`BlockTicks.MaxRandomTicksPerChunk`	`8`	Random ticks per chunk per pass
`BlockTicks.MaxChunksPerPass`	`512`	Chunks processed per pass
`BlockTicks.MaxMainThreadBlockTicksPerPass`	`5000`	Cap on block ticks on the main thread per pass
`BlockTicks.AdaptiveUnderOverload`	`true`	Lowers block ticks when the server is under load

Pregeneration

Pregeneration builds terrain ahead of player movement. It is on by default and pauses while players are online.

Key	Default	Effect
`Pregen.Enabled`	`true`	Turns pregeneration on
`Pregen.PauseWhenPlayersOnline`	`true`	Pauses while any player is connected
`Pregen.PauseBelowTps`	`15.0`	Pauses when TPS falls below this value
`Pregen.MaxColumnsPerSecond`	`500`	Chunk columns generated per second

To turn pregeneration off:

/stratum set Performance.Pregen.Enabled false

Check its state with /stratum pregen.

Timer resolution (Windows only)

On Windows the default timer resolution is about 15.6 ms, which caps a server near 25 TPS. Stratum sets it to 1 ms at startup.

Key	Default	Effect
`TimerResolution.Enabled`	`true`	Applies the 1 ms setting. Has no effect on Linux
`TimerResolution.PeriodMs`	`1`	Timer resolution in milliseconds

The timer is set at startup, so restart the server after you change these values.

Physics and simulation distance

Key	Default	Effect
`Physics.Enabled`	`true`	Turns physics tick throttling and activation ranges on
`SimulationDistance.Enabled`	`true`	Turns the distance limits on
`SimulationDistance.RandomTickDistanceBlocks`	`96`	Random ticks run only within this distance of players
`SimulationDistance.BlockGameTickListenerDistanceBlocks`	`128`	Block game tick listeners run only within this distance of players

Where to start

Run /stratum timings to see where tick time goes.
If chunk sending dominates, look at ChunkSending and Join.
If entity simulation dominates, read Entity tick throttling.
If autosave spikes come at a regular interval, look at AutoSave.
If block ticks dominate on a large or heavily farmed world, look at BlockTicks.
If the server is busy when nobody is online, check Pregen.