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  1. Core Server
  2. SERVER-54685

wrong definition of MONGO_YIELD_CORE_FOR_SMT for arm64

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    Details

    • Type: Bug
    • Status: Closed
    • Priority: Major - P3
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: 4.9.0, 4.2.13, 4.4.5
    • Component/s: None
    • Labels:
      None
    • Backwards Compatibility:
      Fully Compatible
    • Operating System:
      ALL
    • Backport Requested:
      v4.4, v4.2
    • Sprint:
      Dev Platform 2021-03-08

      Description

      MONGO_YIELD_CORE_FOR_SMT is defined as the yield instuction, but yield is just a nop in arm64.

      Using an "isb" instruction is a better implementation. The Instruction Synchronization Barrier will create a very small delay without taking other CPU resources, which is required while spinning on a spinlock.

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              Assignee:
              acm Andrew Morrow
              Reporter:
              tsahee@amazon.com Tsahi Zidenberg
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                Updated:
                Resolved: