JDK-8276066 : Reset LoopPercentProfileLimit for x86 due to suboptimal performance
  • Type: Enhancement
  • Component: hotspot
  • Sub-Component: compiler
  • Affected Version: 11,17,18
  • Priority: P4
  • Status: Resolved
  • Resolution: Fixed
  • Submitted: 2021-10-27
  • Updated: 2022-12-16
  • Resolved: 2021-11-03
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JDK 11 JDK 17 JDK 18
11.0.14Fixed 17.0.2Fixed 18 b23Fixed
Related Reports
Relates :  
JDK-8149421 - Vectorized Post Loops
Description
The performance was observed to be suboptimal on x86 with LoopPercentProfileLimit=30.

It seems better to reset it to the original value (10) for x86.
Comments
Fix request I'd like to backport this fix to jdk17u and jdk11u to fix the performance degradation when post loop vectorization is disabled. Patch can be applied cleanly. It only resets LoopPercentProfileLimit from 30 to 10 on x86. So the risk is low. Thanks.
04-11-2021
Changeset: 0ab910d6 Author: Jie Fu <jiefu@openjdk.org> Date: 2021-11-03 22:45:50 +0000 URL: https://git.openjdk.java.net/jdk/commit/0ab910d626a05106e1366438aeb5b16e16374c2f
03-11-2021