JDK-8272774 : Allow heap region sizes larger than 32M with larger card table entry sizes
  • Type: Enhancement
  • Component: hotspot
  • Sub-Component: gc
  • Affected Version: 18
  • Priority: P4
  • Status: Closed
  • Resolution: Duplicate
  • Submitted: 2021-08-20
  • Updated: 2021-11-19
  • Resolved: 2021-11-19
The Version table provides details related to the release that this issue/RFE will be addressed.

Unresolved : Release in which this issue/RFE will be addressed.
Resolved: Release in which this issue/RFE has been resolved.
Fixed : Release in which this issue/RFE has been fixed. The release containing this fix may be available for download as an Early Access Release or a General Availability Release.

To download the current JDK release, click here.
Other
tbdResolved
Related Reports
Duplicate :  
JDK-8275056 - Virtualize G1CardSet containers over heap region
Relates :  
JDK-8272773 - Configurable card table card size
Relates :  
JDK-8152438 - Threads may do significant work out of the non-shared overflow buffer
Description
JDK-8272773 investigates the impact of configuring the card table sizes, essentially allowing larger card table entry sizes.

Since G1 ties remembered sets to card table entry size, enlarging these would allow larger heap region sizes. 

Investigate the impact of larger regions on applications; most likely this would affect (large) applications with many remembered set entries the most, so using something like BigRAMTester for evaluation would be useful.

Maybe determine a heuristic that with larger heap sizes scales the card table entry size and the (maximum) heap region size.
Comments
Suggested by V. Chand (https://mail.openjdk.java.net/pipermail/hotspot-gc-dev/2021-August/036197.html)
23-08-2021