RFR(S)JDK-8214074: Ghash optimization using AVX instructions

[Kamath, Smita]

Hi Florian,

The performance gain that I reported was over the earlier implementation of GHASH using clmul instructions (generate_ghash_process_blocks).
 
Regards,
Smita

-----Original Message-----
From: Florian Weimer [mailto:fweimer at redhat.com] 
Sent: Monday, November 19, 2018 1:55 PM
To: Kamath, Smita <smita.kamath at intel.com>
Cc: 'Vladimir Kozlov' <vladimir.kozlov at oracle.com>; Anthony Scarpino <anthony.scarpino at oracle.com>; core-libs-dev at openjdk.java.net; hotspot compiler <hotspot-compiler-dev at openjdk.java.net>
Subject: Re: RFR(S)JDK-8214074: Ghash optimization using AVX instructions

* Smita Kamath:

> I'd like to contribute an optimization for GHASH Algorithm using AVX 
> Instructions. I have tested this optimization on SKX x86_64 platform 
> and it shows ~20-30% performance improvement for larger message sizes 
> (for example 8k).

Performance improvement against what?  The pure Java implementation?  I find this a bit surprising.  I would have expected a much larger performance improvement from the use of CLMUL instructions.

Thanks,
Florian