AI Improvements: Performance Tuning guide for All the Mods 10 0.51

Same as in the All the Mods 10 8.1 guide

AI Improvements: Performance Tuning is a small, server-minded mod that makes vanilla mob AI cheaper to run. It also lets you switch off certain AI behaviors. It targets problems like too many animals and performance hits from swarms of zombies.^[1]

This pack ships version 0.5.3 of the mod. It has been in the pack since 2.25 or earlier.^[2]

How it helps

Most of the gain comes from caching heavily calculated values. That cuts CPU time at the cost of an ignorable amount of RAM. The main feature replaces the game's EntityLookHelper with a more efficient version that stores data to find the angle to a location faster. The author's VisualVM testing showed a 50% to 80% decrease in CPU usage by the AI code. On a server with 25 people online constantly, that meant a gain from 5 to 7 tps.^[1]

The mod also has two optional switches. One removes the AI segment that makes mobs turn their heads toward a nearby entity. The other removes the 'look idle' AI. The author says both can free up CPU, with the visual cost of odd or missing head rotation. The project page describes both as off by default.^[1]

Who it is for

It is built for large, heavily modded servers where mobs and other entities eat into CPU time. You can install it on the server only, since it works without a client-side copy. Client-only installs are possible, but it may not do much for your fps.^[1]

Unverified The sources do not show how the pack configures this mod, so the defaults described above come from the mod's project page and are not confirmed as this pack's values. They also do not show any quest or ATM Star path involvement, so there is no progression step tied to it.

Same as in the All the Mods 10 8.1 guide

This one is different from most mods in the pack: AI Improvements: Performance Tuning isn't something you craft or build with. It works quietly in the background, making vanilla mob AI cheaper to run and letting you switch off certain AI behaviors. So your first steps are about testing and settings, not items.^[1]

Unverified The sources here show no recipes, quests or guidebook entries for this mod, so there is no first item to craft. The option defaults below are the mod's own defaults from its project page, and the sources here do not show whether the pack changes any of them.

What to do first

1. Measure before you decide. The mod's author says it isn't expected to improve performance in every case, so test your results to see whether you actually need it.^[1]
2. Know where it runs. It can be installed on the server only, which is the setup it grew out of. It also works on the client only, though it may not do much for your FPS there.^[1]
3. Set your expectations. Newer Minecraft versions already include AI fixes, such as the rotation fix, so the gain is much smaller than in older versions.^[1]
4. Find the config. The project page says the mod's config file is at .minecraft/config/bbm/AI_Improvements.cfg.^[1]

The main options

The project page describes these config options, with the defaults the mod ships with. Most of the savings come from caching heavily calculated values, which trades a negligible amount of RAM for less CPU time.^[1]

• Disable AI Watch Closest Entity: off by default. When on, it removes the AI segment that makes mobs turn their heads toward nearby entities. It frees up a lot of CPU, but you may notice some odd visuals.^[1]
• Disable AI look random: off by default. When on, entities stop using the idle look AI. This can help servers with large populations, and the only visible effect is that heads sometimes don't rotate, which mostly goes unnoticed.^[1]
• Replace EntityLookHelper with a more efficient version: on by default. If you turn it off, you won't see much AI improvement, though the other disable options should still work fine.^[1]

This mod has no machines, multiblocks, power or fluids to worry about, it doesn't add a single item or block to the game. Everything it does happens at runtime on entity AI: it swaps one piece of vanilla mob code for a faster cached version, and it can strip individual AI goals off mobs before they ever start ticking. All of that is driven by one config file, entity.general.allow_remove_calls, so "using" the mod means editing values there rather than building anything.^[1][3]

The design goal is straightforward: a server's CPU time gets eaten by entity AI as populations and mob counts grow, and most of the savings here come from caching heavily calculated values, trading a negligible amount of RAM for less CPU time. The author is upfront that it won't help in every case, so test your own results rather than assuming a win.^[1]

The look controller replacement

This is the main feature, and it's turned on in this pack: entity.mob.replace_look_controller.replace_look_controller is set to true. It replaces the default look controller with a version that uses cached tan math, storing some data that makes working out the angle to a location much faster. It only applies to vanilla-style mobs: if a mod overrides the look controller on its own entity, the replacement is skipped for that mob.^[1][3]

Testing with VisualVM showed a 50% to 80% decrease in CPU usage by the AI code, and on a server with 25 people online constantly it moved the tick rate from 5 to 7 TPS. Disabling the replacement won't break anything, but you lose most of the gain from the AI code itself; the other disable options still work on their own.^[1]

How goal removal works

The removal side is gated by a master switch, entity.general.allow_remove_calls, which is true in this pack. It allows AI tasks to be removed from entities at runtime; if you set it to false, none of the per-mob or per-mob-type removals below will run at all, no matter how you set them.^[3]

Alongside it, entity.general.enable_call_bubbling is also true here. It lets repeat remove calls bubble to the top of the list, which improves performance when the same mob type spawns over and over, exactly the situation you get with a mob farm or a swarm.^[3]

Mob-wide look settings and filter lists

Two settings apply across mobs generally rather than to one species, and both are false in this pack. entity.mob.remove_look_goal.remove_look_goal removes the look-at-goal task that makes AIs face a player or attack target, which also means they won't face walking directions. entity.mob.remove_look_random.remove_look_random removes the look-at-random-position task, which makes mobs feel a little lifeless because they no longer animate head movement while idle.^[3]

Each of those two settings, and the look controller replacement, has its own pair of filter options. The filter_list holds the mobs the setting applies to, and is_allowlist decides how that list is read: true applies the setting to all mobs on the list, false applies it to everything except the mobs on the list. In this pack all three lists are empty and all three is_allowlist flags are false, so nothing is being excluded.^[3]

• entity.mob.remove_look_goal.filter_list and entity.mob.remove_look_goal.is_allowlist control which mobs lose the look-at-target goal.^[3]
• entity.mob.remove_look_random.filter_list and entity.mob.remove_look_random.is_allowlist control which mobs lose the idle head movement.^[3]
• entity.mob.replace_look_controller.filter_list and entity.mob.replace_look_controller.is_allowlist control which mobs get the cached look controller.^[3]

Per-animal task removal

Chickens, cows, pigs and sheep each get the same family of toggles, and every one of them is false in this pack, so vanilla farm animals behave exactly as normal until you change something. The shared options are remove_breed (the animal can no longer breed to create offspring), remove_float (it no longer swims in water), remove_follow_parent (babies no longer follow their parents), remove_panic (it no longer runs around after being hit or searches for water to extinguish itself), remove_stroll (it no longer walks around randomly) and remove_tempt (it no longer follows a player holding an item it likes).^[3]

Sheep get one extra: entity.sheep.remove_eat_block removes the eat-block task, so sheep stop eating grass and can no longer regenerate their wool. It's false in this pack.^[3]

Fish have their own set, all false here: entity.fish.remove_swim takes away the random swimming pathfinder so fish hold position more often, entity.fish.remove_panic stops them running away, entity.fish.remove_avoid_player stops them avoiding players, entity.fish.remove_follow_leader stops them schooling behind a leader fish, and entity.fish.remove_puff stops puffing up when entities are nearby.^[3]

Client, server and automation

The mod is coded to work without being installed client-side, so it's safe as a server-only addition; it also runs client-only, though it won't do much for your FPS there. There's no item pipeline, power system or automation to interact with: the only "tuning" you do is in the config file, and it takes effect on the entities the game spawns.^[1][3]

Unverified The mod's project page lists an older config path for a previous Minecraft version. In this pack the settings live in the common TOML config shown above; whether the older file is read at all here is unconfirmed. The TOML file also contains a few further options beyond those documented in this section.

Everything for this mod lives in one file, config/aiimprovements-common.toml. Most of its options are switches that strip a single AI behavior from an animal, and the pack leaves nearly all of them off, so your farm animals and fish behave like normal vanilla ones.^[3]

What the pack turns on

Only three options are set to true in this pack, and they are the ones doing the performance work.^[3]

• entity.mob.replace_look_controller.replace_look_controller is true. It swaps the default look controller for a version with cached tan math, which improves performance. It only works on vanilla-style mobs, and it skips any mob whose look controller is overridden by a mod.^[3]
• entity.general.allow_remove_calls is true. This is the master switch that lets AI tasks be removed from entities at runtime. If it is disabled, no per-mob or per-mob-type removals run at all.^[3]
• entity.general.enable_call_bubbling is true. It lets repeated remove calls bubble to the top of the list, which helps when mobs spawn repeatedly.^[3]

What the pack leaves untouched

Every per-animal removal toggle is false in this pack. That covers chickens, cows, pigs and sheep (breeding, floating, following parents, panic, strolling and tempting), plus fish and squid behaviors. Sheep also have an eat-block toggle. Nothing is stripped from these mobs unless you change it yourself.^[3]

The mob-wide look options are also off: entity.mob.remove_look_goal.remove_look_goal and entity.mob.remove_look_random.remove_look_random are both false. Their filter lists are empty and is_allowlist is false.^[3]

Unverified The sources don't list the mod's own default values, so I can't confirm which of the settings above the pack changed from default.

There isn't much history to cover for this one. All the Mods 10 0.51 ships AI Improvements: Performance Tuning at version 0.5.3 (file AI-Improvements-1.21-0.5.3.jar), and the pack has included it since 0.32 or earlier.^[4]

Mod changelog

• 0.5.3: updated to Minecraft 1.21.^[5]

Unverified Pack changelog entries for this mod are not shown in the sources here, so what changed for it between individual All the Mods 10 releases is unverified. The pack's own changelogs are where that detail would live.