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  1. JDK
  2. JDK-8173398

limit number of GC worker threads for smaller heaps

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    Details

    • Type: Enhancement
    • Status: Closed
    • Priority: P3
    • Resolution: Duplicate
    • Affects Version/s: 9
    • Fix Version/s: 10
    • Component/s: hotspot
    • Labels:
    • Subcomponent:
      gc
    • CPU:
      generic
    • OS:
      generic

      Description

      The heuristics currently do not seem to take the size of the heap into account when calculating the default number of worker threads. This can often lead to a huge amount of thread overhead for small heaps. As an extreme example, on a on a 40 HW thread machine, 9-ea+144 will start up over 100 GC threads (G1) OOTB for a 16m heap.

      This has caused performance issues in environments where many small processes are run in parallel.

      This ER is to document the issue and prompt a discussion on whether we can improve the ergonomics for smaller heaps.

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              Assignee:
              Unassigned Unassigned
              Reporter:
              dbuck David Buck
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                Created:
                Updated:
                Resolved: