RFR: 8068736: Avoid synchronization on Executable/Field.declaredAnnotations

[Joel Borggrén-Franck]

Looks good.

cheers
/Joel

> On 15 jan 2015, at 13:32, Claes Redestad <claes.redestad at oracle.com> wrote:
> 
> Hi,
> 
> please review this patch to use double-checked locking to avoid
> synchronization overhead on repeated access to the
> declaredAnnotations field in Executable and Field.
> 
> webrev: http://cr.openjdk.java.net/~redestad/8068736/webrev.00
> bug: https://bugs.openjdk.java.net/browse/JDK-8068736
> 
> Testing: jtreg java/lang
> 
> Benchmarking:
> - no significant changes in a small set of SPEC benchmarks
> - up to 4x in micros focused on repeated access to the
> declaredAnnotations field, both in single- and multithreaded setups
> - less than 5% cost (not statistically significant) on micros accessing
> the declaredAnnotation map of a method only once.
> 
> /Claes