JDK-6735527 : Bitmap - speed up searches
  • Type: Enhancement
  • Component: hotspot
  • Sub-Component: gc
  • Affected Version: hs14
  • Priority: P3
  • Status: Resolved
  • Resolution: Fixed
  • OS: generic
  • CPU: generic
  • Submitted: 2008-08-08
  • Updated: 2020-08-08
  • Resolved: 2018-11-02
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 12
12 b19Fixed
Related Reports
Relates :  
JDK-8179004 - Add an efficient implementation of the "count trailing zeros" operation
Relates :  
JDK-6735522 - Bitmap - force inlining of find_next_one_bit()
Relates :  
JDK-8251322 - Improve BitMap::iterate
Description
The search functions in the BitMap class could use alternative methods to locate the next one bit instead of the simple for loop currently implemented.
Comments
Related paper: Kazuya Morikawa, Tomoharu Ugawa, and Hideya Iwasaki. 2013. Adaptive scanning reduces sweep time for the Lisp2 mark-compact garbage collector. In Proceedings of the 2013 international symposium on memory management (ISMM '13). ACM, New York, NY, USA, 15-26. DOI=10.1145/2464157.2466480 http://doi.acm.org/10.1145/2464157.2466480
15-07-2014
EVALUATION One user reported noticeable speedups of parallel compaction, which uses bitmap searches heavily, after implementing search using table lookup.
08-08-2008