JDK-8247843 : Reconsider G1 default GCTimeRatio value
  • Type: Enhancement
  • Component: hotspot
  • Sub-Component: gc
  • Affected Version: 16
  • Priority: P4
  • Status: Resolved
  • Resolution: Fixed
  • Submitted: 2020-06-18
  • Updated: 2025-07-10
  • Resolved: 2025-07-09
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JDK 26
26 b06Fixed
Related Reports
Blocks :  
JDK-8238687 - Investigate memory uncommit during young collections in G1
Relates :  
JDK-8353716 - G1: AHS work umbrella
Relates :  
JDK-8349978 - G1: Retune G1 GCTimeRatio boosting during heap expansion for small heaps
Description
In JDK-8238687 G1 will make committed heap more or less follow the GCTimeRatio. Which means that there may be throughput regressions due to keeping a smaller heap now.

Further in the last few years, pauses have been optimized a lot, now taking significantly less time.

So it is natural to think about rebalancing the GCTimeRatio default value decision made years ago.
Comments
Changeset: 47614796 Branch: master Author: Ivan Walulya <iwalulya@openjdk.org> Date: 2025-07-09 05:44:42 +0000 URL: https://git.openjdk.org/jdk/commit/4761479608d5a8ecc504e343109900b0d0c77171
09-07-2025
A pull request was submitted for review. Branch: master URL: https://git.openjdk.org/jdk/pull/25832 Date: 2025-06-16 14:05:52 +0000
16-06-2025
Liang Mao from Alibaba mentioned that "for online interactive applications" something like 20 would be used in their setups. E.g. https://mail.openjdk.java.net/pipermail/hotspot-gc-dev/2020-June/030132.html
18-06-2020