Massive CPU Usage while idle, no players

[Blazedd]

Title: Massive CPU Usage while idle, no players

Version: 3.0.3/3.0.4

OS: Centos 6.2 (Final)

Java Version: 1.7.0 JDK

Description of Problem:

Forward: I'm one of the lead techs at a MineCraft Hosting Company. We have a custom built monitoring system that lets us see our server boxe's cpu and memory usage in real time.

Server Specs:

i5 3.1 GHz quad core

16GB DDR3 RAM

Dedicated SSD Drive for MC servers

(pretty much all you need to know)

Today I noticed that we had all 4 cores almost maxing out. After looking further into it I noticed that it was caused by two Tekkit servers. They had between 12-16 threads a few of which were consuming massive amounts of CPU. Looking further into we found these servers were completely empty and have been for hours. We had our server maxing out it's CPU because of two empty servers. One server has 2GB ram and the other has 1GB ram.

5 minutes after restarting one of the tekkit servers we saw this in htop: http://puu.sh/C5gg

We really want to continue offering tekkit servers to our customers, but we can't risk stability of the servers to the Tekkit servers not taking up all of the CPU power. If there isn't an address to this issue we will simply have to drop Tekkit.

Error Messages:

No Messages in Console, no spam, nothing

[jjd210]

I too am having this problem, my host is not happy :/ i have tried removing all plugins but CPU usage continued to be very high. In fact i tried a clean install of Tekkit 3.0.3 on my own personal server and running idle it was using 80-95% of a dual core 1.5GHZ processor, so it must be something to do with tekkit

[aldrigviking]

what plugins are you using?

[jjd210]

as i just said it runs with extremely high CPU usage with no plugins or pre used maps etc "clean install"

[penorzilla]

JJd210 you have a 1.5 ghz processor so here you go: www.newegg.com

Now to respectively address the OP.

With tekkit having 1000 ways to increase CPU load time, are you simply looking at the "Online players" or the actual console? Sometimes tekkit will crash with a high CPU load, will basically kick all players and present 0 errors.

Another thing could be "Chunk loaders". No players need to be online, but the server will mimic a player being online by keeping chunks loaded. As you can already assume, this would mean High CPU load time could occur even with 0 players online.

I would try to get your client to create a new map and see if the problem occurs.

[redranger]

I've found this too. Since 3.0.3 I'm getting a lot of complaints about lag, having checked top I'm finding Tekkit servers all over the place sucking the CPU from the servers. I've stopped offering Tekkit to new clients but I'm not really sure how to get existing clients off Tekkit until this can be fixed. It's just not worth hosting it if it's going to cause all other servers on that machine to lag.

[Jay?]

Are these new worlds or old worlds that have been converted?

Care to post your logs, folks?

Also, OP, is there any way you could test the server without your special monitoring program? they could be interacting badly.

[redranger]

The only error messages I'm getting is this one:

http://forums.technicpack.net/threads/3-0-3-3-0-4-java-io-ioexception-invalid-utf-8-first-byte-89.11253

Otherwise here's a full startup log:

http://pastebin.com/Qz34u0dN

Here's what top is giving me:

The top two are the only Tekkit servers on this server. 38/48% is low, it normally drifts between 80%, 400% and 600%. One of them is empty, the other has 4 players online.

The same thing is happening on other machines, load averages on machines with Tekkit are between 10-30, when they used to be 4-6. Machines without Tekkit are fine.

[Jay?]

Hm. I have puzzlement. I see ragnar couldn't help you much either. I'll see if i can get someone more knowledgeable to help.

[Cheap Shot]

19:45 <sct> The reason for that - is a bug in that version of craftbukkit

19:45 <sct> craftbukkit 1.2.5-R1.3

19:45 <sct> It had a huge issue where with 0 plugins installed

19:46 <sct> it would just sit and idle at 100% cpu

19:46 <sct> happens on certain machines

19:46 <sct> Tekkit 3.1 with the new forge will have a fix

19:47 <sct> [for now] All he needs to do

19:47 <sct> is put in ONE plugin

19:47 <sct> like worldguard

Quoting sct on the matter.

The issue only happens if you have zero plugins. Just add one, it can be any plug in at all, and you will bypass this issue.

[jjd210]

i can see your point about having plugins installed but i still had a problem when i converted to 3.0.3 which had a clean world but plugins installed

[KakerMix]

i can see your point about having plugins installed but i still had a problem when i converted to 3.0.3 which had a clean world but plugins installed

Had or still have? Also this is information for the OP, not just you so don't be so quick to discount advice because this isn't your thread.

[jjd210]

sorry, just trying to provide as much information as i can. I still have some lag issues but now have a populated map

[redranger]

Not to intrude on someone else's thread but adding a plugin doesn't seem to have made a difference to the exact same issue that I'm facing on my servers.

[Blazedd]

Adding a plugin to resolve the CPU usage seems to be counter intuitive to logic and reason. There has to be a "better" solution out there.

[Jay?]

Adding a plugin to resolve the CPU usage seems to be counter intuitive to logic and reason. There has to be a "better" solution out there.

It's a bug. Did you bother following the advice before dismissing it?

[KakerMix]

Adding a plugin to resolve the CPU usage seems to be counter intuitive to logic and reason. There has to be a "better" solution out there.

Did you even try?

I'm not exactly sure what you want us to do about it, I suppose you could go scream at the the people behind craftbukkit itself and claim that they are terrible people and how dare they have a bug. Coping at attitude (or doing a weird condescending 'logic and reason' tirade) certainly isn't going to win you any friends. Or anybody willing to help you for that matter.

[redranger]

Did you even try?

I'm not exactly sure what you want us to do about it, I suppose you could go scream at the the people behind craftbukkit itself and claim that they are terrible people and how dare they have a bug. Coping at attitude (or doing a weird condescending 'logic and reason' tirade) certainly isn't going to win you any friends. Or anybody willing to help you for that matter.

I really don't think he meant it in a condescending way, I don't know why you're taking it that way.

He had a valid point, especially since I'd just said that I tried this and it didn't work for me and we have exactly the same problem.

What's with all the attitude on these forums? If you don't have anything nice or productive to say surely it's better not to waste yours or other people's time?

[Jay?]

What's with all the attitude on these forums? If you don't have anything nice or productive to say surely it's better not to waste yours or other people's time?

A large part of it is that the last few days have been goddamn ridiculous. the other part is that he said that it didn't make sense for it to work, and asked for us to provide him a fix, without actually trying it first.

[Blazedd]

@KakerMix The issue would NOT be on craftbukkit, otherwise our craftbukkit servers we setup without plugins would have the same issue. The different variable is Tekkit, not craftbukkit. Also a login and reason "tirade" is because we are dealing with a logical system. It's not like we are handling something that won't do exactly as it's programmed to do. We cannot force our clients to run a single plugin or any specific number of plugins in any arrangement. All we can do is report the issue and hope for the best. However you are both assuming that we've not tried it. Someone else already told you that that didn't work, no reason repeating what's already been said.

At this point we are arguing about everything but the problem at hand.

[Jay?]

Okay, but since you run servers, you should know that different systems don't always react the same, and that two bugs that look like the same thing aren't always the same thing.

So please, seriously, you came here to get help with your bug, and we gave you advice. If you aren't going to try the advice before dismissing it, what do you want from us?

[Blazedd]

But you see, i didn't dismiss your solution before trying it. You assumed I did. Read my last post. Seriously I haven't demanded a single damn thing from you. I've done nothing but report the problem and get an edgy reply. Rather than creating a shitstorm of drama over who did what can we PLEASE fucking get to the point where we try our hardest to supply information, figure the problem out, fix it, and move on. If you don't want to fix the solution, don't have time, or don't care let us know. You create the forum for bugs, I placed my bug, and I'm trying to help. You've done little to contribute by comparison of helpful vs spiteful replies.

I don't expect anything from a free project, but I didn't expect to have to fight on a forum about petty things like this.

[Jay?]

You never actually told us whether you did or not, you just told us we were assuming you did, and then say that the fix wasn't practical, and didn't work for someone else. you also didn't do was tell us what the result of trying it was.

Realistically though, if it's a problem with the server, and you cant get your clients to use a plugin, your options are to set up frequent auto restarts and wait for the next server update, or use a previous version.