JDK-8057000 : Increase parallelism in String deduplication fixup
  • Type: Enhancement
  • Component: hotspot
  • Sub-Component: gc
  • Affected Version: 8u40,9
  • Priority: P4
  • Status: Open
  • Resolution: Unresolved
  • Submitted: 2014-09-01
  • Updated: 2019-02-11
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In CRM Fuse, string deduplication table fixup takes a significant amount of time (~25-30% of average gc pause time).

One interesting thing noticed is that only around half of the threads actually do work. This may be due to startup/synchronization taking so long for many threads.

This is also somewhat similar to the problem described in JDK-8040120.

One option to fix this is to merge string deduplication work with other parallel tasks in the "Other" group if possible.
See if this is still a big problem after the changes for JDK-8087324, and potentially reprioritize.