Hey!I'm trying to figure out the cause of some severe TPS lag in a custom 1.20.1 Forge modpack:
https://modrinth.com/modpack/hexcraft
and could use some help interpreting a Spark profile. The game is running at around 3–5 TPS, and everything feels like it's in slow motion...mobs move slowly, actions delay, etc. When I run /forge tps, the Overworld is around ~150 ms and the Nether ~180 ms, so it doesn’t seem isolated to one dimension.
I’ve already run Spark and noticed a lot of time being spent in things like Level.getEntities, EntitySectionStorage, and general entity iteration. There’s also a big chunk (~24%) going to Pehkui, specifically getInteractionBoxWidthScale(), which makes me think something is constantly recalculating entity size or hitboxes. I do have Size Shifting Potions installed with reach modifiers enabled, along with other mods that might hook into scaling (Vampirism, Werewolves, etc.).
The pack is pretty heavy (~200+ mods), including things like Create + Valkyrien Skies/Clockwork, Ice and Fire, Alex’s Mobs, MCA Reborn, Legendary Survival Overhaul, and sanity systems—so I know there’s a lot going on. I’m just trying to figure out what’s actually driving the lag: whether it’s mainly too many entities, some mod doing excessive per-tick calculations, or something specifically abusing Pehkui.
Here’s the Spark profile: https://spark.lucko.me/xkuFxAPn9p
If anyone can take a look and point out the main bottleneck or most impactful fix, I’d really appreciate it. I’m not trying to gut the pack, just want to understand what’s actually causing the slowdown so I can tune it properly. Im not very techy so feel free to download the pack and play around yourself!