JDK-8242164 : Obsolete -XX:UseAdaptiveGCBoundary
  • Type: CSR
  • Component: hotspot
  • Sub-Component: gc
  • Priority: P2
  • Status: Closed
  • Resolution: Approved
  • Fix Versions: 15
  • Submitted: 2020-04-05
  • Updated: 2020-04-08
  • Resolved: 2020-04-08
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Description
Summary
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Obsolete the VM product option `UseAdaptiveGCBoundary`.

Problem
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This feature has had a long bug tail of crashes and performance regressions; it is not clear that it has ever fully worked.  The most recent attempt to enable it by default appears to have occurred in 2005, and was soon reverted.  Recent retesting was able to provoke crashes with JDK 9, 11, 12, 13, and 14.  The most recent associated bug (JDK-8228991) was deferred from JDK 13 and again from JDK 14.  The Oracle GC team doesn't consider it a priority to (attempt to) fix this feature.

Solution
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Obsolete the option and remove the feature implementation.

Because the feature controlled by this option

* appears to have never worked reliably (see linked related bugs), despite repeated attempts,
* has been disabled by default for a long time (since before Mercurial), and
* doesn't show up as being mentioned as useful in internet searches,
* fixing the feature is not considered a priority,

immediately obsoleting the option is preferred to having an initial deprecation period.

Specification
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Use of `-XX:+/-UseAdaptiveGCBoundary` will no longer enable or disable the feature. Instead, using this option will print the usual obsolete option warning.

Comments
Moving to Approved.
08-04-2020