Minecraft Finally Gets Multi-Threaded Servers

[GhostRoadieBL]

Summary

 It took many years but PaperMC have cracked multi-threaded servers for Minecraft. Due to 99% of mods being single threaded, the server mod is still vanilla MC but the codebase is available on GitHub so expect some of the more popular mods to transition to multi-threaded server support. 

Quotes

Quote

A Minecraft world is split up into worlds (such as the nether or the overworld) and chunks. Chunks are 16x16xZ vertical columns of blocks. Folia breaks up sections of chunks into regions that can be ticked independently.

My thoughts

 This is huge! I know there are only a few servers which would actually hit the required player counts to need multi-threading but to be able to host potentially thousands of players in a single world could, theoretically, introduce competition to Fortnite, Roblox and other large player world games and expand minecraft's use cases. There are already themepark and museum servers which will undoubtedly benefit from reducing their server costs with wasted threads idle.

 

Sources

https://hackaday.com/2023/04/03/minecraft-finally-gets-multi-threaded-servers/

[dcgreen2k]

I might be crazy, but aren't Minecraft servers already multithreaded to some degree? I've definitely seen cases where my Minecraft servers have used >50% CPU usage on a Ryzen 7 4800h. It looks like this modification is specifically for chunk ticks, which is certainly interesting though.

[jaslion]

I think the main thing for this is similar how older mmo's did engine reworks to put more players together. Increase the look and feel of it being a very active community even if only a couple hundred people are online.

 

This has been a proven strategy to keep interest in the game and pull new people in as well you see fellow players so that means there is active stuff going on and thus you might want to pull in some friends because the game doesn't look dead.

 

Also super happy it happened because there is another HUGE thing here. People using older slow systems at home for a mc server with some friends can now continue using their old pc instead of having to upgrade.

[jaslion]

2 minutes ago, dcgreen2k said:

I might be crazy, but aren't Minecraft servers already multithreaded to some degree? I've definitely seen cases where my Minecraft servers have used >50% CPU usage on a Ryzen 7 4800h. It looks like this modification is specifically for chunk ticks, which is certainly interesting though.

Sorta. It's a single thread that can direct other threads to do certain tasks. But this thing seems to take away a lot of the load of that single thread and spread it out.

 

So basically the scheduler for everything now has less to do which means it can do more of what it still needs to do. I'll have to try this out on the old nas we used to use as a mc server with a athlon 5150 that stopped being good enough a while ago.

[dcgreen2k]

2 minutes ago, jaslion said:

snip

I see. I've been programming for a couple years, including with Java, but I don't have much experience with multithreading. Definitely an interesting addition though.

[jaslion]

5 minutes ago, dcgreen2k said:

I see. I've been programming for a couple years, including with Java, but I don't have much experience with multithreading. Definitely an interesting addition though.

Honestly multi threading is skipable in 95% of the use cases BUT is super handy when you can have a task that can be spread out over many cores that will take a while :p.

 

That or your project lead promises up to 8 core multi threading for your project that is something quite basic and is all serial in nature and needs to work step by step to function so you have to bs the hell out of things and show activity on 8 cores :D.

[E-waste]

1 hour ago, jaslion said:

Also super happy it happened because there is another HUGE thing here. People using older slow systems at home for a mc server with some friends can now continue using their old pc instead of having to upgrade.

I also thought of this as I read the post, glad I'm not the only one!

[E-waste]

1 hour ago, jaslion said:

I'll have to try this out on the old nas we used to use as a mc server with a athlon 5150 that stopped being good enough a while ago.

Wow!  I've been wanting AM1 system for quite some time.  There were still a few ebay sellers with them, but I couldn't quite budget it out.  I wonder if those have found a home yet, and if there are others wanting to sell them, I sure hope so.

 

25 watt TPD and decent GPU support.  It is a limited platform, but it would make a great low power x86 server!  I just have the xeon system, it idles around maybe 40-45 watts or so (I haven't measured it with my current low power setup, so that's a total guess).  I know it's around 52 at 3.2 Ghz base wifh EIST enhanced intel speed step enabled.  So assuming it must be lower than that now.

[Kisai]

2 hours ago, GhostRoadieBL said:

Summary

 It took many years but PaperMC have cracked multi-threaded servers for Minecraft. Due to 99% of mods being single threaded, the server mod is still vanilla MC but the codebase is available on GitHub so expect some of the more popular mods to transition to multi-threaded server support. s/

 

Java has had multi-threading since it's ineception, in like 1997 or something. I distinctly remember this. Why don't more programs use multi-threading? Because multithreading and multi-core systems were not really a thing until about 10 years later. That is well before Minecraft.

 

But game developers often don't care about threading because it's difficult to break a game into threads. In induces a lot of latency. The go-to has been "coroutines" which is basically not threads, and doesn't scale to multi-cores.

 

Even Unity, still doesn't multi-thread things. If you want threads, rewrite your game to use Unreal Engine. AI is particularly good at being threaded, but you can't create 1000 threads for a world of 1000 "AI" objects. you're probably going to create one thread per type (Eg spiders, ducks, cats, villagers, etc) and have that thread apply the same piece of logic to each instanced object.

 

So a "multithreaded" mod for a game that operates on a native multithreaded environment seems like a no-brainer really. But I can't imagine it being viable unless mods are re-written to be aware of it, because a big thing in multi-threading in other languages (eg perl, php, python, javascript) is that nobody uses the threading in it, because it ultimately doesn't work. It makes things too complicated. If the task you need isn't perfectly parallelizable, you don't thread it. You use the threads to do different tasks to avoid stepping on each other, and that's it. A game ultimately will likely never use more than 2-3 threads because too much is timing sensitive (eg input and netcode) to have to wait for locks.

 

 

[jaslion]

6 hours ago, E-waste said:

Wow!  I've been wanting AM1 system for quite some time.

Dont its shit and a waste of money

 

Mine idles at around 35w because the cpu is constantly near 60% just trying to exist it is super slow.

 

Fyi tdp does NOT equal wattage consumed. It often goes to 55w or more.

[Jerakl]

Nice. Hopefully modding follows suit. I know we ran into tick issues on my modded server when multiple bases started to get developed 

[porina]

10 hours ago, Kisai said:

Java has had multi-threading since it's ineception, in like 1997 or something. I distinctly remember this. Why don't more programs use multi-threading? Because multithreading and multi-core systems were not really a thing until about 10 years later. That is well before Minecraft.

I don't know if there was anything earlier, but more than one core/thread started to be popularised in enthusiast area by the Abit BP6 motherboard released in 1999. You could slap two Celerons in that for what was then a kicking machine. I had a pair of Celeron 366 bus overclocked to 550 MHz, also forcing me to move from Win9x to Win2k to support it. I don't recall any consumer software using more than one thread at the time, but it helped with multi-tasking regardless. Mainstream multi-thread may have been Intel's introduction of Hyper-Threading in 2002. AMD bought dual core to the masses in 2003.

 

10 hours ago, Kisai said:

If the task you need isn't perfectly parallelizable, you don't thread it. You use the threads to do different tasks to avoid stepping on each other, and that's it. A game ultimately will likely never use more than 2-3 threads because too much is timing sensitive (eg input and netcode) to have to wait for locks.

This is likely a main problem. A lot of things just can't be scaled well across parallel threads. Something will be critical path, and that will still limit ultimate performance. I wouldn't be so hard to say something needs to be perfectly parallelisable to be worth it. Prime95 shows a performance (efficiency) loss as you assign ever more threads to a worker, but this often still works out better than running more workers with fewer threads due to limitations elsewhere.

 

Not sure what games do, but they do scale to more threads than ever. On my own system I've seen performance scaling of Watchdogs Legion where running the full 12 cores of my system performs clearly better than limiting it to 8. I was hoping any clock increase from limiting to 8 would help more. TLOU for all its problems can max out the CPU especially at higher settings. Games must be doing something with all that CPU.

[Kisai]

3 hours ago, porina said:

 

 

Not sure what games do, but they do scale to more threads than ever. On my own system I've seen performance scaling of Watchdogs Legion where running the full 12 cores of my system performs clearly better than limiting it to 8. I was hoping any clock increase from limiting to 8 would help more. TLOU for all its problems can max out the CPU especially at higher settings. Games must be doing something with all that CPU.

DX12/Vulkan games use more threads because they were designed to, where as DX9 and OpenGL can't actually get over 1 thread for rendering. There's simply no way to do that. Java has generally used OpenGL, and that's why things like "RTX" doesn't actually work on it, because to get such features requires intercepting those OpenGL calls with something that actually uses Vulkan.

 

Like Portal RTX is really just Portal + DXVK+asset swaps.

 

[jagdtigger]

I hope the other modded server developers will be able to implement it, paper devs have a few decisions i dont quite like (like ripping out the chat report feature, or at least making it an option).....

[williamcll]

On 4/7/2023 at 9:32 AM, Kisai said:

But game developers often don't care about threading because it's difficult to break a game into threads. In induces a lot of latency. The go-to has been "coroutines" which is basically not threads, and doesn't scale to multi-cores.

Shocking how such a large company struggle to do multithread on a game that operates on 30 ticks after 10 years of development. 

 

Even more shocking is that Bedrock edition also suffers from this despite not built on Java.

[dcgreen2k]

13 minutes ago, williamcll said:

Shocking how such a large company struggle to do multithread on a game that operates on 30 ticks after 10 years of development. 

 

Even more shocking is that Bedrock edition also suffers from this despite not built on Java.

Because multithreading the game to this degree wasn't worth the development effort, especially when the scenario this modification is made for is an edge case. It's obviously possible, but there isn't much that can be fully parallelized in the game without requiring a complete rewrite or ending up breaking an existing part of the game. From a developer's perspective, if a task can't be perfectly parallelized, then the vast majority of the time it will be written to run on a single thread. There's a reason this modification specifically targets chunk ticks, since chunks can be grouped into regions that act independently of each other.

[manikyath]

this has been done douzens of times, and it always results in:

- other things breaking

- duping bugs

- random glitches when things interact between threads

 

the only thing that is single threaded in minecraft is the tick thread (world gen and networking should be at least partially threaded iirc.) and the solution here is just to move things *out* of the tick thread that dont belong there, instead of breaking up the very thing that makes duping in vanilla minecraft actually exceptionally rare...