RFR: 8170595: Optimize Class.isAnonymousClass

[Mandy Chung]

Hi Claes,

What is the performance difference if this method calls getSimpleBinaryName?  Your patch exposes the implementation details and sensitive to the change there, if any.

Mandy

> On Dec 1, 2016, at 5:38 AM, Claes Redestad <claes.redestad at oracle.com> wrote:
> 
> Hi,
> 
> due to recent interest to optimize Class.isAnonymousClass[1] I took
> a look at the implementation and found that we can further improve
> performance of this method, especially when asking non-anonymous
> classes[2].
> 
> As such calls are a common occurrence during startup and bootstrap
> of lambdas this actually appears rather worthwhile:
> 
> Webrev: http://cr.openjdk.java.net/~redestad/8170595/webrev.01/
> Bug: https://bugs.openjdk.java.net/browse/JDK-8170595
> 
> Thanks!
> 
> /Claes
> 
> [1] http://mail.openjdk.java.net/pipermail/core-libs-dev/2016-December/045116.html
> [2]
> Benchmark                       Mode  Cnt    Score    Error  Units
> Clazz.isAnonymousClass_Anon     avgt   50  200.900 ± 15.503  ns/op
> Clazz.isAnonymousClass_Regular  avgt   50  136.896 ±  9.605  ns/op
> 
> Clazz.isAnonymousClass_Anon     avgt   50  186.564 ± 12.219  ns/op
> Clazz.isAnonymousClass_Regular  avgt   50   33.878 ±  1.524  ns/op
> 
> See bug for benchmark source