JDK-8150364 : Clear CT phase work distribution too fine-grained
  • Type: Enhancement
  • Component: hotspot
  • Sub-Component: gc
  • Affected Version: 9
  • Priority: P4
  • Status: Closed
  • Resolution: Duplicate
  • Submitted: 2016-02-22
  • Updated: 2017-04-12
  • Resolved: 2017-04-12
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.
JDK 10
10Resolved
Related Reports
Duplicate :  
JDK-8153507 - Improve Card Table Clear Task
Description
In the Clear CT phase threads race to clean the card tables for regions. They claim regions using atomic operations.

Testing found that the distribution granularity of the card table of a single region is too small: profiling with hardware counters indicate that the atomic operation is a significant part of the pause.

Fix this by changing the way G1 remembers regions that need cleaning and improve the ratio between useful work and synchronization
Comments
Initial tests on a prototype shows that on x86 you can get 33% reduction in clear ct time "for free"
22-02-2016