CPU usage through the roof!

Discussion in 'Bukkit Help' started by arkwolf, May 16, 2011.

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    Hey guys we are having huge problems with bukkit at the moment and we need help ASAP!

    We run a duel quad core server with 24gb on xeon 5560 CPU's. If we host a vanilla minecraft server our CPU usage is 1-4%.

    As soon as we try bukkit builds 766, 740 or 733 we get HUGE lag increases. With 4 people on Vanilla we get 1-4% and on bukkit its 30% both with no plugins.

    We need help ASAP! Can someone recommend a build or a fix to this CPU usage!
    gamingvortex likes this.
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    Are you actually getting lag, or just seeing higher cpu usage?
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    I will post our results, The builds of bukkit we used were 766, 740 and 733.

    1-2 people
    Vanilla: 3% max cpu, no lag
    Bukkit: 15% max cpu, no lag

    Vanilla: 5% max cpu, no lag
    Bukkit 25% max cpu, 3 second chat lag

    Vanilla: 8% max cpu
    Bukkit: 30%+ cpu, huge lag spikes
    The results occured on ALL the builds we tried

    It is true that internet connection at the moment is nothing crash, But I was playing on lan and noticed lag. But I dont see how it could be the CPU causing the lag since they are pretty powerfull.
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    were you using plugins?
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    I myself am surprised, the game weighs 50 mb server 7Mb, and such claims.. the horror..
    iPhysX likes this.
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    The like is for the facepalm Lion.
    pomo4ka likes this.
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    I played by 20-25 people a day, 24 hours server eats 3.500 MB RAM. CPU fluctuates 80-90%. However, no lags. Anyway sorry to ruin the car.
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    I did already say "with no plugins" in my first post, Can any1 confirm they are having the same problems with these builds? or can anyone do a test?

    I am using the latest Java and Windows server 2008
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    Bukkit runs on one core, so the load.
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    0.o bukkit runes on a single core? that can not be right... i watch the cpu's and it uses all cores
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    Does it fluxuate between which core it is using?
    Or is it using both cores :eek:
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    It would not be using both cores, that would be impossible, unless you are running multiple worlds and I haven't been informed of multi-threaded worlds yet... So it's not using multiple cores I'm guessing.
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    Minecraft consumes only 1 core - only garbage collection could take another one

    Iam running with amd dualcore @ 2,6ghz and 4 players

    0 player - 5% , cpu load on 1 core
    1 player - 20%, cpu load on 1 core
    2 player - 35%, ...
    3 player - 50%, ...
    4 player - 65%, ...

    peaks are reaching 70 or 80%
    using debian squeeze and we got no lag even cpu is up to 100% on one core

    you should check your java installation and java parameters
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    cd "${0%/*}"; java -D64 -XX:ParallelGCThreads=3 -XX:+AggressiveOpts -Xshare:auto -Xshare:auto -jar craft.jar
    0 player 0.50%
    5 20%
    10 30%
    28 89% (had outhers from a syster server come over)
    and about oh id say 20 plugins or so >:)
    here is my start file plese done bash it works very well
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    I've been noticing this CPU thing lately myself. Thought it was because of the modifications I made to the world generator (I think I did the chunk caching wrong) but I think its something else possibly.

    Maybe even a plugin? I'll get 20 players on tonight vanilla craftbukkit and see if the cpu usage is still there.
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    well all i know is when I use taskmgr on our server, since its duel quad cores with hyper threading it shows it using more then 1 core, infact it seems to use 4 cores +
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    Java's garbage collection can use multiple threads, and some plugins can break out functions into separate threads, but minecraft server itself is a single thread.
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    As soon as our server is out of the post, I will record a utube video and show what is happening.
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    I also noticed that...
    World is loading very slowly and sometimes there occurs lags while using bukkit.
    There is at the moment only one solution for this. Use the original server software.

    But the solution is sometimes nearer than expected, the CPU is not the Problem here. Okay that may seem much, but don't forget that Bukkit this is a project of Indie developers, and it wasn't made by performance junkies. I was thinking about your RAM...

    Maybe try to launch the server with 1 or 2GB more of RAM.

    Second issue could be: You are hosting locally at home with a slow Internet connection -> big difference between vanilla and bukkit.
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    Getting a lot of feedback that this is happening as well with worlds loading slowly.
    AMD Opterons 6128 thrive on multi-cores, and MC being single core just plain crushes them. 10 Players here and we overload, which oddly wasn't the case in 1.4. (10 = 35%)

    Java changing helped about 5-10%, but thats not enough to host 50, ha! If only MC was multi-threaded then we'd be in the clear here.

    Slow maps only just started during 1.5, which is really strange. Same configuration as it was in 1.4, just slower.
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    They did release an update improving lag and cpu usage but i think they need to release another one.. There is always a HUGE problem with JAVA because the platform in general uses high cpu usage. Is there a way of allowing it to use more then one core?
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