JDK-6440724 : 1.5.0: CMS: misleading preclean and abortable preclean statistics
  • Type: Bug
  • Component: hotspot
  • Sub-Component: gc
  • Affected Version: 5.0u6,6
  • Priority: P3
  • Status: Resolved
  • Resolution: Fixed
  • OS: generic
  • CPU: generic
  • Submitted: 2006-06-20
  • Updated: 2014-02-24
  • Resolved: 2006-08-09
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Other
1.4.2_14Fixed
Description
See comments section.
Comments
SUGGESTED FIX Archived data: /net/prt-archiver.sfbay/data/archived_workspaces/1.5/tiger_update9_baseline/2006/20060727104049.asaha.hotspot/ Webrev: http://analemma.sfbay.sun.com/net/prt-archiver.sfbay/data/archived_workspaces/1.5/tiger_update9_baseline/2006/20060727104049.asaha.hotspot/workspace/webrevs/webrev-2006.07.27/index.html Webrev: http://jpsesvr.sfbay.sun.com:8080/ctetools/CodeStore/1875/webrev/webrev.html ====================================== Fixed 6440724: 1.5.0: CMS: misleading preclean and abortable preclean statistics [###@###.###,###@###.###,###@###.### Brief Description of the problem being fixed : The precleaning timing stats are misleading because of a bug in the use of timers. This came to light during some recent performance tuning work for an important client. Platform affected : ALL Does this fix need Forward ported ? NO Fixed by : ###@###.### Backported by : ###@###.### Putback by : ###@###.### Code Reviewed by (2 reviewers required) : ###@###.###,###@###.###,###@###.### Is this fix for a JPSE introduced regression ? NO Is the testcase(if available) provided for the regression testbase ? NO Has this fix been verified by customer(s) ? NA Test information : On Windows or Linux run: java -XX:+UseConcMarkSweepGC -XX:+PrintGCDetails -XX:CMSInitiatingOccupancyFraction=2 ... (for example, jbb) will show correct (non-zero) precleaning times; previously you'd see precleaning times of zero.
27-07-2006
EVALUATION The fix was made in Mustang a while back as part of normal Mustang development but was not backported because of process oversight.
20-06-2006
SUGGESTED FIX Change the following: 2965 CMSPhaseAccounting(this, "preclean"); to: 2965 CMSPhaseAccounting pa(this, "preclean"); and similarly for the following: 2991 CMSPhaseAccounting(this, "abortable-preclean"); to 2991 CMSPhaseAccounting pa(this, "abortable-preclean"); The first change above also applies to the 1.4.2 code base and should be fixed in 1.4.2_13, see subCR.
20-06-2006