RFR[XS] JDK-8178543 - Optimize Klass::is_shared()

coleen.phillimore at oracle.com coleen.phillimore at oracle.com
Thu Apr 13 12:15:11 UTC 2017

This looks good.  Glad there was an access flag bit left.


I'd make it #ifdef ASSERT instead.  I don't think anyone's built 
optimized in a long time tho.


On 4/13/17 5:30 AM, Ioi Lam wrote:
> Hi, please review this small start-up enhancement:
> https://bugs.openjdk.java.net/browse/JDK-8178543
> http://cr.openjdk.java.net/~iklam/jdk10/8178543-klass-is-shared.v01/
> We have a benchmark that shows Klass::is_shared() is called very 
> frequently during InstanceKlass::link_class_impl, and costs about 2% 
> of the start-up time.
> The fix is simple -- instead of walking the list of CDS shared 
> regions, use a new bit in Klass::_access_flags
> Thanks
> - Ioi

More information about the hotspot-dev mailing list