RFR: 8170595: Optimize Class.isAnonymousClass

[Claes Redestad]

Hi,

sadly, avoiding getSimpleBinaryName is where most of the gain comes 
from, avoiding
getSimpleName only improves marginally on the baseline:

Benchmark                       Mode  Cnt    Score    Error  Units
Clazz.isAnonymousClass_Anon     avgt   10  192.522 ± 33.214  ns/op
Clazz.isAnonymousClass_Regular  avgt   10  115.770 ± 19.953  ns/op

Wrapping the checkPermission call inside getEnclosingMethod so that
Reflection.getCallerClass() doesn't happening improves things a bit, but 
still
not close:

Clazz.isAnonymousClass_Anon     avgt   10  187.074 ± 38.128  ns/op
Clazz.isAnonymousClass_Regular  avgt   10   96.196 ± 15.709  ns/op

/Claes

On 2016-12-01 17:57, Mandy Chung wrote:
> 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