RFR: 8209862:CipherCore performance improvement

[Anthony Scarpino]

On 10/01/2018 06:11 AM, Seán Coffey wrote:
> JDK-8207775 introduced some performance regressions in the ciphercore 
> area. Sergey Kuksenko has been looking at this and has contributed the 
> following patch:
> 
> http://cr.openjdk.java.net/~skuksenko/crypto/8209862/
> bug report : https://bugs.openjdk.java.net/browse/JDK-8209862
> 
> I've been reviewing it and ran functionality and TCK testing. Didn't see 
> any issues. Sergey has also confirmed that the patch helps to alleviate 
> the performance issues introduced. More details regards approach for fix 
> are in the bug description.
> 
> Thanks Sergey! I'm looking for another review from security team.
> 


A minor change maybe to move the declaration of finalBuf on line 1040 
into the if() below, then return the finalBuf in the if.  Then remove 
the else and return 'input'
---
   if ( ...
      byte[] finalBuf;
      ...
      return finalBuf;
   }
   return input;
}
---

I don't think this should hurt performance at all, maybe just a few less 
instructions

Tony