High CPU usage, lag and poor performance on dedicated / integrated servers

https://bugs.mojang.com/browse/MC-117611?focusedCommentId=458596&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-458596

Reply to Neko: If this is now an issue again, the status on MC-117611 by logic, is re-opened?

@unknown I think MC-117611 is still valid, but it describes high tick delay and extreme lag (which is still present currently in 1.13-pre1).

This ticket (MC-118106) also describes high resource usage (CPU & RAM) in more detail, along with the very bad lag and high tick processing time.

I get big lag spikes even when generating empty chunks or playing on superflat worlds.

Affects 1.13-pre7

Still an issue in 1.13-pre10.

I have a single server running, with one player logged on, on an entire dedicated box - Intel i7-7700k @ 5GHz, 64GB RAM and NVMe storage - and I'm seeing the same issues.

Confirmed for release 1.13.

Until this bug is fixed, rather than being a simple boon, pregeneration will be a mandate for all (even small) survival server owners who want their players to have a decent experience.

In previous releases, pregeneration was nice, but I hardly did it because my servers were mainly for a few people and we experienced no lag at all.

Affects 18w31a, TPS still decreases to about 8-9 when generating new chunks.

It seems like 17w47b is the 1.13 snapshot that added extreme lag from exploding TNT (MC-135529 and MC-133867). Exploding TNT in snapshots 17w47a and below is the same as 1.12.2.

Confirmed for 18w33a.

Still Unassigned in more than a year?
Confirmed in EVERY 1.13 snapshot.
Playing 1.13 on a multi player survival server is near impossible. The tick lag / client server sync is so far off it is near unplayable. Example: Bridging over a ravine, the void, the nether, you place a block, you see the block, you move to said block... the block is now gone and so are you... and all that you've worked for. Misplace a gravity block while in water and you take a ride down into the void. A hostile mob attacks me, I attack back, the hostile mob floats in the air while I perform a "Matrix" move on it. I'm not that OP. I watch videos were what once could be done now is near impossible, all the while playing on a respectable white listed SMP server experiencing the exact same issues. Missing items from player inventory, furnaces that only smelt some of the items yet burn the fuel for all of them. When the server restarts, the game is somewhat playable, and yet predictably becomes more and more unplayable in a short period of time.
I am sorry Mojang but I feel like I'm beta testing right now. I'm not sure how I can help, but this is really bad. Please help me help you.

i've noticed myself on my server machine running 18w46a that the server instantly pings the CPU at 100% on a brand new map regardless of how many players are on and eventually times out to watchdog

Yes, and the server starts to lose TPS fairly quickly after a restart.

100%, single thread, server on Ubuntu entirely unusable in this format. Tried all sorts of java arguments, no dice.

This needs fixing asap!

Watching the recent changelogs and bugs being fixed, but apparently this is not a priority, shame!

Confirmed, still seeing this behavior in 19w04b.  As a multiplayer (LAN Shared) client, to get the chunks to load, I have to disconnect and reconnect.  After that, as a client, it will forever be stuck on "Waiting for chunk".

Still in 19w07a

Confirmed, still a problem in 19w07a.  I am running my multiplayer world on a lightly loaded Linux server as follows:

$ java -server -Xms2048M -Xmx8192M -jar server.jar nogui

With only two players it is hardly usable - we frequently have to reconnect to get the chunks to render.

This is on a new world , created with 19w07a.  We aren't using command blocks or redstone and have not spawned any mobs that didn't spawn on their own (and no breeding).

Still in 19w08a

Still a problem in 19w09a

Still in 19w13a

Still in 19w14a

My server network just made a 1.14 pre release 1 server and have noticed the same thing it will constantly post the error Can't keep up! Is the server overloaded? and it will be running as low as 30-50 behind as high as 500 behind. Updated today to pre release 2 and still having the same issues. Its causing my players to not want to play on vanilla minecraft as they say its badly optimized and not playable. Please get on this issue as soon as you can its game breaking at this point.

With 3 people on running Pre4 my RAM usage dosent go above 10.5% & CPU usage fluctuates between 34% to 45%

Still in 1.14 pre-5

Wow! Still in 1.14 Release! It's sooooo bad! We have the impression that we came back in 2018 with the first snapshots of the 1.14 with the new rendering engine!

How was it done to regress at this point? It was not too bad in Pre-Releases...

At least they fixed it from idling at 100%. I am noticing a lot of my 1.14 servers have horrible CPU waste.  A lot are idling around 20-30%, a few at 40-50%, and the rest (Most) at 15%.  But it takes SO LONG for it to get down to 15%.  And the Ram usage in 1.14 is horrible.  A Vanilla server needing 2GB of ram at idle is ridiculous.  I know Java Edition can't be milked dry for money like the other platforms, but they could at least care for it a bit more.  Or actually respond to us.  

Xeon E3 1270 V6 3.8Ghz

1.14 was very fine for my server, CPU usage stayed below 60% even with 10 players on, with next to no lag except for funny chunk loading.

Now in 1.14.1 Pre-Release 1, chunk loading is fine, but the server is clogging the entire CPU again and we're experiencing pretty bad entity and block lag with the same number of players. I'll watch the server when it's idle again.

It's slightly better for me in 1.14.1, but it still only takes about 10 minutes of play for it to overheat my computer, in singleplayer, with all the settings turned down. I never had these problems in 1.13. 

It's better than before but still in 1.14.1 Release

I can see that the issue was created for version 1.12. I used to run the server on 1.12 but on version 1.14.1 server runs at least twice as slow. I'm using vultr and 1.12 server run just fine on 20$ subscription. Now I'm running 1.14.1 server and it's lagging and using 100% CPU on 40$ subscription. It really sucks...

Just twice as slow? Compared to 1.12? Lucky you!
My server runs three times slower, compared to 1.13.2...

Powerful server always running perfectly smooth on 1.13.2 - after upgrade to 1.14.1 with a new world generated the server can't keep up even with 10 players and with render distance lowered to 6 (was 15 on 1.13.2):

• enormous resources usage, eating up to 16 GB of RAM in a matter of a couple of hours, even with server limited to 10 slots only;

• CPU also enormously stressed most of the time;

• basically, resources usage is at least about 3 times higher than it was on 1.13.2;

• frequent crashes due to high resources usage, low tps, lags;

• logging in by someone takes very long and is causing terrible lags on the server;

• people are often getting timed-out kicks.

@@unknown
 
While this ticket (MC-118106) is indeed about performance issues, it is more about long standing structural issues. If you have experienced a massive change within 1.14 then it is more likely that you are experiencing both MC-138550 and MC-118106.
 
You really should look into MC-138550. It's an acute issue that has arisen during the 1.14 shapshots that has been partially resolved several times but it keeps returning with a vengeance. If MC-138550 does appear to be impacting you please show your support on that issue as we're not even sure if Mojang acknowledges it as a legitimate issue as we haven't seen any official communication as of yet.
 
I hope that helps.
 

The problem is less in 1.14 than it was in some earlier snapshots, but despite high resource usage the server still lags behind quite often and for a long time, sometimes seconds at a time. I still run 1.7.10 and older, which even with mods don't come close to the same resource usage nor experience the fairly extreme timeouts. With two players using the same connection to a server less than 400miles away on a completely barren map still use 60% of 800% total is not acceptable, especially when timeouts and lag are still present. The fact this issue is being completely ignored, while other completely trivial bugs seem to get more attention is disgusting, shame on you Mojang!

Amen!

Just discovered something: Disabling mob spawning removed all signs of the lag. At 40 players it performed exactly as it should on a $120/month machine.

What I mean is that entities should not have affected performance as much as they have, that is remove the problem completely. It's likely the performance leak is somewhere in there.

@MetoolDaddy

This confirms my opinion also.

Recently after many days of observations I discovered - and now I'm 100% positive about it - that one of major impacts of server-side performance is broken new AI of mobs, especially pillagers and patrols. My server keeps stable 20 TPS but when I meet a patrol TPS starts to drop and after wiping out the patrol it is raising again back to 20. I think this is something very critical that devs should look into to make the game playable again.

The performance drop did begin before 1.14 though. Maybe we're dealing with an entirely different issue by now?

This bug report might just be too broad.

@Kamil Pigłowski @MetoolDaddy Yes, I can confirm that disabling mob AI and/or spawning greatly improved the performance in certain scenarios like mob farms, large spaces with spawn-able platforms, etc. However, the server performance overall seems to have dipped way down in recent versions (1.13 / 1.14), compared to older stable versions like 1.11 and 1.12.

According to my observations and tests the major hit in performance, as expected, is still caused by chunk generation/loading, entities, mob spawning and AI.

This ticket is focused primarily on that, along with some additional info on how the gameplay is affected. I don't really know if the stated details cover too large area, but if other tickets contain all specific points that are listed here, maybe this one should be split and carried over?

To be honest, there are way too many small bits of details about performance issues in hundreds of tickets to keep track of, let alone filter and create separate report for every single one.

I'm open to suggestions on what could be changed here, or if the mods decide to close and split the ticket if needed.

So I shifted my world to Minecraft Realms and it was great at the beginning but after 3 weeks of playing it gets really laggy again. In terms of content versions 1.13 and 1.14 are great but it's almost unplayable on multiplayer servers

1.14.4 Survival SMP whitelisted server launched today. Roughly 48 players on and off. Within the first 2 hours the server had crashed at least 3 times. Rubber banding, block lag, near zero chunk loading, cannot eat, cannot pickup items. My dog would never teleport to me even. You can't travel by boat or horse since the server complains it moved to fast. This is insane and purely SUCKS! The SMP experience is being ignored in my opinion. While I'm on a rant, it's interesting that the 1.14.x lighting glitch seemed to go temp fixed/ignored until Hermitcraft tweeted about the issue.

@xavom

Unfortunately Mojang seem to think that everything's fine with the current state of the server; I certainly have not seen any acknowledgement from Mojang about the terrible state of affairs or any plan to investigate or resolve the issue. Mojang could be working on it, but if they are they aren't talking. I have seen community moderators asking for profile data, but there is no sign that the data is actually making it to anyone at Mojang. It's pretty much been radio silence. And, for the hosting community, this has had a massive impact, which makes the lack of communication even more hard to deal with.

Here's is Mojang's current solution to your problem: buy better hardware. For your needs (48 players SMP) all you need is a 1024 core 300Ghz Xeon CPU, 512TB of RAM and a 2TB/sec SSD. I am sure you can get one of those for cheap at your local PC store, right? It's not like their current published hardware recommendations are total garbage...

1.14 has been a disaster. It's generated a lot of renewed community interest, which has meant higher than usual server loads, which all would have been fine if 1.14 wasn't also a total dog in the performance stakes. For nearly a decade the hosting community was a huge part of Minecraft's success, but the double punch of Realms and Mojang's ongoing hostility to the hosting industry is making it very hard to provide servers for the community.

Unfortunately Mojang seem to think that everything's fine with the current state of the server

Incorrect. Mojang is aware of the situation and planning for further performance improvements in 1.15.

So far I also have not seen a single ticket about a specific performance issue. So far everything I've seen was just "help my minecraft is laggy / has bad performance". That's not particularly helpful. Also, so far nobody (as far as I can tell) has posted a debug report that shows bad server performance, or what the bad server performance is coming from.

I want to add that this ticket at this moment of time is just "Server performance in MC 1.12 and above is bad". If someone could find out exactly why that is, the chances that performance can be improved soon is increased significantly.

There is hard to tell about a specific performance issues because the whole 1.14+ and still 1.14.4 is one big performance issue. There were tons of specific reports for example in https://bugs.mojang.com/browse/MC-138550 but the ticket has been closed. Besides, players who paid for the product are not your employees. Maybe hire your own quality control or beta testing team. Let this team just start a good-hardware server and make it for 10-20 people. Let that team play the game normally for a couple of days, explore, trade, breed, fly elytra, do some raids, just play the game normally and you will see how dramatically bad it is comparing to 1.13.2 (not even to 1.12.2). You will see for yourselves how many lag spikes freezing the game even for a couple of seconds there are, how many TPS drops below 10 there are, and how many general lags and shutters there are. Figure it out yourselves why is that, do reports on your own. When players are trying to help giving you most accurate info possible comming straight from their gameplay and attaching tons of reports like in https://bugs.mojang.com/browse/MC-138550 then the biggest ticket like this one is... closed...

MC-138550 was closed because it contained literally every issue ever with performance and was not specific in any way, shape or form. The developers did not know how to handle it, so it was closed.

If you're not willing to help with resolving the issue, then why complain here? This is a community bug tracker, managed by us volunteers, which happens to be used and hosted by Mojang. Yes, if Mojang wants to search for the causes by themselves, they of course can do that, but don't be surprised if it takes ages for the performance improvements to take effect.

As a matter of fact, I haven't seen a single debug report since the release of 1.14.4 that shows any bad server performance here on the bug tracker.

About debug reports - maybe this is because after 1.14.4 you have closed the most important ticket about performance and stated that 1.14.4 is final 1.14 release and there will be no more performance fixes and you now focus on releasing 1.15 in which you eventually might start working on performance again. So people just gave up.

I also have the same problems and I can even show it using an image as I host both 1.12.2 servers and one 1.14.4 server, and if you look at the image that I have attached, it is the upper one being the 1.14.4 server with 1 player on, and the lower one a 1.12.2 server with 1 player on.
I have chosen to strip all other things as they are not necessary to illustrate it.

I'am sending the debug report in the next message, so only the Users can see it.

The server have:

2x Intel Xeon E5603
Minecraft Server have 8 GB RAM
The operating system is Windows Server 2016 64bit
Java Version: 1.8.0_201 64bit

Sometimes the Minecraft server with 1.14.4 stops itself and reports that it is doing so because it is running too many ticks behind.

I get this message right after I restart the server, even if no players are joined.

[16:31:37] [Server thread/WARN]: Can't keep up! Is the server overloaded? Running 2364ms or 47 ticks behind

This ticket seems to have devolved into a thread for complaints, rather than being constructive. As this is a bug tracker and not a discussion forum, we ask that further conversation about this ticket, performance, and other topics be taken to the Mojira Subreddit.

Any further comments here should be constructive to the resolution of this problem, including providing debug reports and profiler logs, steps to recreate the issue, or other helpful insights on the problem at hand.

As the creator of this ticket has stated though, the scope of this report is becoming broad, and may need to be split up to address specific performance issues. Discussions around that should also be left to the subreddit.