To what extent is Minecraft multi-threaded?

[Jipthechip]

I’ve heard that while Minecraft is technically multi-threaded, it is a primarily single threaded game because it does most of the work in a single thread. Is this true?

If so, does that go for servers as well as clients? Would a Minecraft server be able to fully utilize a processor with 8 or even 16 threads, or would a few of these threads not be utilized?

Edited June 3, 2019 by Jipthechip

[Erumaaro]

I am playing modded 1.12.2, and my w7 taskmanager says that my minecraft javaw.exe uses 46 threads.... and i have a 4core/4 threads  cpu (ItelCore2 QuadCPU Q9400).

Could someone explain what that means?

[Erumaaro]

thats what i thought, so is minecraft 1.12.2 (+forge asm) actually using multithreading then?

[Kiljaeden053]

Sorry for necroing @diesieben07 but what is the entirety of "main game logic" is single threaded. I mean specifically.

[Kiljaeden053]

18 hours ago, diesieben07 said:

Updating entities, updating blocks, everything that "happens in game".

Specifically everything Mojang coded. so having separate cores for updating entities, blocks, would make the game faster.

[DavidM]

16 minutes ago, Kiljaeden053 said:

Specifically everything Mojang coded. so having separate cores for updating entities, blocks, would make the game faster.

Except that would break every world interaction as well as cause a ton of concurrency issues.

Adding more threads doesn’t mean the game would be faster and better; threading is not a magical solution to all performance issues.

 

Threading should only be used if the routine to be put on another thread makes sense to be on another thread (i.e. make the checking for update routine separate from the main game thread, or separate the render thread from the game logic thread (not Minecraft specific)). It is not as simple as totalTimeUsed / threadCount = actualTimeUsed.

Edited May 31, 2020 by DavidM

[Kiljaeden053]

29 minutes ago, DavidM said:

Except that would break every world interaction as well as cause a ton of concurrency issues.

Adding more threads doesn’t mean the game would be faster and better; threading is not a magical solution to all performance issues.

 

Threading should only be used if the routine to be put on another thread makes sense to be on another thread (i.e. make the checking for update routine separate from the main game thread, or separate the render thread from the game logic thread (not Minecraft specific)). It is not as simple as totalTimeUsed / threadCount = actualTimeUsed.

In your opinion. What would be the best solution to make the game more optimized on large servers?

[DavidM]

8 minutes ago, Kiljaeden053 said:

In your opinion. What would be the best solution to make the game more optimized on large servers?

Depending on the game type of the server, it may be more up to how server plugins are written rather than the game itself (i.e. mini game servers rely heavily on the performance of the mini game plugins).

 

As for optimizing the game itself, projects like Spigot provide tweaked server jars that might improve server performance.