JDK-6787254 : Work queue capacity can be increased substantially on some platforms
  • Type: Enhancement
  • Component: hotspot
  • Sub-Component: gc
  • Affected Version: 5.0u15,5.0u16
  • Priority: P3
  • Status: Resolved
  • Resolution: Fixed
  • OS: generic
  • CPU: generic,x86
  • Submitted: 2008-12-19
  • Updated: 2010-05-06
  • Resolved: 2009-03-25
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.
Other Other JDK 6 JDK 7 Other
5.0u18-rev,hs11.3Fixed 5.0u19Fixed 6u13-revFixed 7Fixed hs11.3Fixed
Related Reports
Relates :  
JDK-6821693 - 64-bit TaskQueue capacity still too small
Relates :  
JDK-2176686 - Alignment problem in GC taskqueue
Relates :  
JDK-6786503 - Overflow list performance can be improved
Description
The Age field can be 64-bit in the 64-bit JVM because
of the availability of a 64-bit CAS. The resulting increase
in workqueue capacity should reduce the incidence of slow-paths
to deal with overflow handling; see for example CR 6786503.
Comments
EVALUATION Never mind; we can't have "fix failed" and then "duplicate". Will leave in state "fix delivered" but all backporters of this bug fix should know that its intentions did not take effect, and the real fix is being done in 6821693.
25-03-2009
EVALUATION The intended change in this CR never took effect because of unintended (but thankfully benign) bugs (in this changeset) that are being fixed in 6821693. Marking this CR as fix failed and dup'ing to 6821693.
25-03-2009
EVALUATION http://hg.openjdk.java.net/jdk7/hotspot/hotspot/rev/23673011938d
05-02-2009
EVALUATION http://hg.openjdk.java.net/jdk7/hotspot-gc/hotspot/rev/23673011938d
31-01-2009
EVALUATION Deleted.
21-01-2009
SUGGESTED FIX Preliminary shape of the changes (by no means final):- http://analemma.sfbay.sun.com/net/neeraja/export/ysr/workqueue/webrev
12-01-2009
EVALUATION The patch for 6787254 will be sent for testing at customer once we have received test results from 6786503. The patch for 6787254 will be additive on top of those of 6786503. While the latter improves the performance in the presence of work queue overflow, the former reduces the chances of overflow with 64-bit heaps by allowing the use of larger work queues.
12-01-2009
EVALUATION An interim patch for the fix has been generated and performance measurements are in progress. Once we are satisfied with the fix, a test binary will be generated for performance tests at the customer.
05-01-2009