Java using multy core but also not

[sajansen]

Hey, I have a modded minecraft server but something is wrong in it. I have 8 cores and 32 GB memory and system wise it looks good. Apart from that java is being stupid. When i start the minecraft server its using 250/300% out of the 800% (8 cores) and when the server is running and started, it refuses to use more then 100% (one core worth of load) even though in top its nicely spread out over multiple cores. java seems to just refuse to use more then 100%. other mods that need processing power can use other cores just fine.

 

Here is a picture of the systemload and it explanes what i mean with java not using more then one core even though its spread out over the cores avalible

 

https://cdn.discordapp.com/attachments/196917843449741312/199356805279776769/Schermafdruk_2016-07-04_04.52.32.png

[RANKSHANK]

Programs have to be written to take advantage of multiple cores. You'll run into the same issue with vanilla. And multithreading Minecraft properly is well out of the scope of forge/modding in general as it's a literal full engine rewrite.

[sajansen]

so, how do the big servers like hypixel do it then? thy seem to be able to run big servers... this screenshot was with just 3 people online... so why? what am i doing wrong? apart from it being modded...

 

indeed, i setup a vanilla server and had the same problem... so system wise it doesnt really meter if its modded or not...i guess

[loordgek]

servers like hypixel link multiple server together using bungeecord  https://www.spigotmc.org/threads/1-8-1-10-bungeecord.392/

[sajansen]

Not all servers do that, the gaming ones do... but if you want a servivel one its run on one server. so its possible, the question is how...

[RANKSHANK]

Not all servers do that, the gaming ones do... but if you want a servivel one its run on one server. so its possible, the question is how...

Jesus christ man. It's not possible for one world survival servers. Those other servers load one world per core since each core can handle one logical thread at a time, leaving the additional cores for things like file loading and networking. A single world's logic IS NOT run on more than one thread. If they do have something for the premium IE Shotbow servers that alleviate some of the load on a separate thread (scoreboard/networking related shizz most likely), then that is an in house solution.

Having multiple, consecutive threads working on the same data in a game is a concurrent access filled nightmare, and half of the life cycle you'd be waiting on some form of access lock to be released when accessing common content.

 

TLDR; Forge does not, and almost certainly(I'm speaking logistically here; not on their behalf) will not split up a world's logical thread for multicore support.