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  1. Minecraft: Java Edition
  2. MC-149018

High Idle CPU usage on Server Edition (Minecraft 1.14 Release)


    • Icon: Bug Bug
    • Resolution: Fixed
    • Minecraft 1.14 Pre-Release 5, Minecraft 1.14, Minecraft 1.14.1 Pre-Release 1, Minecraft 1.14.1 Pre-Release 2, Minecraft 1.14.1, Minecraft 1.14.2 Pre-Release 2, Minecraft 1.14.2 Pre-Release 3, Minecraft 1.14.2, Minecraft 1.14.3, Minecraft 1.14.4 Pre-Release 6
    • None
    • Community Consensus
    • Performance
    • Important

      It seems when Minecraft 1.14 is idle, it still continues to consume CPU at a significantly higher rate than its predecessors like Minecraft 1.13.2


      I've compared the 2 side by side from VisualVM on both Linux and Windows, but I cannot find the cause when I run a snapshot from CPU Sampler. Both results are same, but the CPU consumption is too high on 1.14.


      I have included screenshots from VisualVM running both Minecraft 1.13.2 and Minecraft 1.14


      1.13.2 - Fresh start, No players, Monsters on, Animals on. 1GB RAM Allocated


      1.14: Fresh start, No players, Monsters on, Animals on. 1GB RAM Allocated


      Results did not change when I turned off Animals and Monsters.


      Additional notes: 
      On Windows, the problem is  slightly intermittent... sometimes it might run smoothly and then its almost like something triggers it to go out of idle mode and start munching CPU.
      On Linux the problem occurs 100% of the time.


      A second issue (which could be related) is that Minecraft is consuming up the server thread by 100% nearly all the time. Players join and stay in a single area, but seems like the Server Thread is still doing something way abnormally high. (Appears to be working with chunks, even though chunks are loaded, perhaps a bug in chunk loading / looping?)

      As a result, the server console repeatedly reports falling behind in ticks by 80ms to 2000ms. 

      NOTE: I have found that the second issue is a  known duplicate: MC-138550

      So this bug will now only focus on the first issue, which is high IDLE cpu usage. Minecraft server instance uses a considerable amount of CPU with no players in server. It is also a significant waste of earth resources considering how many instances of Minecraft 1.14 is running around the world.






        1. debug-report-2019-07-02_12.05.12.zip
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        2. firstload.png
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        3. image-2019-04-22-17-22-01-203.png
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        4. image-2019-04-22-17-22-24-609.png
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        5. image-2019-09-25-13-57-54-901.png
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        6. MC server CPU test.jpg
          MC server CPU test.jpg
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        7. minecraft 1.13.2 after 20 mins windows.JPG
          minecraft 1.13.2 after 20 mins windows.JPG
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        8. minecraft 1.14 after 20 mins windows.JPG
          minecraft 1.14 after 20 mins windows.JPG
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        9. mintty_2019-07-04_18-20-40.png
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        10. profile-results-2019-07-02_12.05.07.txt
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        11. Screenshot_2019-04-30_10-24-16.png
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        12. Screen Shot 2019-07-15 at 11.01.51 PM.png
          Screen Shot 2019-07-15 at 11.01.51 PM.png
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        13. Screenshot from 2020-05-25 12-59-39.png
          Screenshot from 2020-05-25 12-59-39.png
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        14. secondload.png
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        15. SERV.png
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            fry [Mojang] Georgii Gavrichev
            ultramoo Mudassar Khan
            59 Vote for this issue
            45 Start watching this issue