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  1. JDK
  2. JDK-8256816

More than 20X slowdown for ManagementFactory.getGarbageCollectorMXBeans()

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    Details

    • Type: Bug
    • Status: Open
    • Priority: P4
    • Resolution: Unresolved
    • Affects Version/s: 9, 10, 11, 12, 13, 14, 15, 16
    • Fix Version/s: 18
    • Component/s: core-svc

      Description

      We noticed a large slowdown from ManagementFactory.getGarbageCollectorMXBeans() comparing JDK 8 and JDK 11. The culprit is probably JDK-8065213, which changes it to call stream().flatMap().collect() underneath.

      Using the attached simple loop program, with -XX:-TieredCompilation, JDK 8 takes ~0.2 seconds, JDK 11 takes ~4.5 seconds.

      This method is important for some programs that repeatedly call it to collect statistics about GC. Such a program could cache the returned list of this method. However, according to JavaDocs, the JVM "may add or remove GarbageCollectorMXBean during execution", so caching is not an ideal solution.

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            Assignee:
            Unassigned Unassigned
            Reporter:
            manc Man Cao
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              Created:
              Updated: