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  1. JDK
  2. JDK-8060092

JEP 242: JVM Trace Events for Failed Allocations

    Details

    • Type: JEP
    • Status: Closed
    • Priority: P4
    • Resolution: Delivered
    • Fix Version/s: 8u60
    • Component/s: hotspot
    • Labels:
    • Author:
      Marcus Larsson
    • JEP Type:
      Feature
    • Exposure:
      Open
    • Subcomponent:
      gc
    • Scope:
      JDK
    • Discussion:
      hotspot dash dev at openjdk dot java dot net
    • Effort:
      M
    • Duration:
      M
    • Alert Status:
       Green
    • Alert Reason:
      On schedule. Code has been committed, but design was simplified to eliminate second JFR event. Tests are being altered to simplify the testing and will be committed by the due date.
    • JEP Number:
      242

      Description

      Summary

      Add trace events to expose information about threads that trigger garbage-collection operations and threads that are waiting for such operations to complete.

      Description

      We will define one new trace event. This event will be sent by threads for which an allocation has failed such that garbage collection is now required.

      In the case of multiple threads triggering GCs at the same time, every thread will send the event. Only one of them will succeed in triggering a GC, however, and that thread will send a garbage collection event. This way one can trace the information about allocations waiting on a GC by looking at the allocation-requiring-gc events (the new event) preceding the garbage collection event.

      The event will contain the allocation size and the id of the pending GC operation.

      The performance impact of generating these events will be negligible.

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            People

            • Assignee:
              pssu Paul Su
              Reporter:
              pssu Paul Su
              Owner:
              Marcus Larsson (Inactive)
              Reviewed By:
              Mikael Vidstedt
              Endorsed By:
              Mikael Vidstedt
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              Dates

              • Due:
                Created:
                Updated:
                Resolved:
                Integration Due: