Many hasRecipe calls, no cache

[cha0s]

Forge Version

40.1.74

Fabric Version

No response

Iron Furnaces Version

1.18.2-3.3.1

Describe your issue

Performance is absolutely terrible.

As you can see, it's all about the recipe lookups:

I tried installing https://www.curseforge.com/minecraft/mc-mods/fastfurnace hoping that its recipe caching would apply to this mod. It doesn't.

This is critical for multiplayer servers. The profile I'm showing is one user's one single furnace on a 2-day-old server. That's absurd.

Crash Report

No response

[cha0s]

My initial thought would be an LRU cache for recipes, set to maybe n * 2 where n is the number of slots in the current factory.

[cha0s]

Just wanted to note that I am having a chance to sit down and look at the code and I already see LRU recipe caches! So there may be more to the problem than I first thought. I am learning more!

[cha0s]

Alright, I worked my way through and found a config option:

[furnaces]
	recipe_cache = 30

to use in ironfurnaces-server.toml. The default is 10. I am going to tune this a bit and experiment.

I'm curious whether you think it might be worth tuning defaults? Or even, implementing a dynamic LRU cache by measuring the amount of recipe requests per n where n could equal 1 tick or 1 second or whatever makes sense after tuning.

[cha0s]

Okay, still digging (do you have a Discord? :))

It seems like tick doesn't even use the recipe cache. getCache is only called once: from getSpeed.

[cha0s]

I think this is the real fix:

diff --git a/src/main/java/ironfurnaces/tileentity/furnaces/BlockIronFurnaceTileBase.java b/src/main/java/ironfurnaces/tileentity/furnaces/BlockIronFurnaceTileBase.java
index a16b4ee..2a908ea 100644
--- a/src/main/java/ironfurnaces/tileentity/furnaces/BlockIronFurnaceTileBase.java
+++ b/src/main/java/ironfurnaces/tileentity/furnaces/BlockIronFurnaceTileBase.java
@@ -892,7 +892,7 @@ public abstract class BlockIronFurnaceTileBase extends TileEntityInventory imple
                 if (e.isBurning() || !itemstack.isEmpty() && !e.getItem(INPUT).isEmpty()) {
                     Optional<AbstractCookingRecipe> irecipe = Optional.empty();
                     if (!e.getItem(INPUT).isEmpty()) {
-                        irecipe = e.getRecipe(e.getItem(INPUT));
+                        irecipe = e.getCache().computeIfAbsent(e.getItem(INPUT).getItem(), (item) -> e.getRecipe(new ItemStack(item)));
                     }
 
                     boolean valid = e.canSmelt(irecipe.orElse(null));

Unfortunately gradlew is hanging when I try to build. Next problem,

[cha0s]

I was able to work through the problems and I was able to stress test. Before the change the furnace tick time was 28ms. With this change the tick time is ~0.2ms once the cache size is tuned.

#124