JDK-8251322 : Improve BitMap::iterate
  • Type: Enhancement
  • Component: hotspot
  • Sub-Component: runtime
  • Affected Version: 16
  • Priority: P4
  • Status: Resolved
  • Resolution: Fixed
  • Submitted: 2020-08-08
  • Updated: 2024-11-20
  • Resolved: 2020-08-10
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JDK 16
16 b11Fixed
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Description
BitMap::iterate could be improved by using count_trailing_zeros instead of looping over the individual bits in a word, much as was done for get_next_one_offset and friends by JDK-6735527.  Rewriting it to use get_next_one_offset would likely both simplify it and make it faster.

It used to be that the deprecated (and now removed) CMS GC was the only user of this function, so improving it wasn't a priority. But it's now being used by CDS (see JDK-8208658, for example), so may be worthwhile now.

Comments
URL: https://hg.openjdk.java.net/jdk/jdk/rev/5418ac229cac User: kbarrett Date: 2020-08-10 14:55:54 +0000
10-08-2020