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

Anthony Scarpino anthony.scarpino at oracle.com
Thu Dec 6 22:24:54 UTC 2018


Hi Smita,

Great, the numbers look better. I'll run the regression tests and push 
it if all goes well.

Tony

On 12/6/18 11:19 AM, Kamath, Smita wrote:
> Hi Tony,
> 
> I have updated my code to address the performance regression in smaller data sizes.
> Please find the updated webrev and JBS link attached.
> 
> JBS link: https://bugs.openjdk.java.net/browse/JDK-8214074
> Webrev link: http://cr.openjdk.java.net/~svkamath/ghash/webrev02/
> 
> Thank you very much for your time and assistance. Please let me know if you have any questions.
> 
> Regards,
> Smita
> 
> -----Original Message-----
> From: Anthony Scarpino [mailto:anthony.scarpino at oracle.com]
> Sent: Wednesday, December 5, 2018 10:56 AM
> To: Kamath, Smita <smita.kamath at intel.com>; 'Vladimir Kozlov' <vladimir.kozlov at oracle.com>
> Cc: Viswanathan, Sandhya <sandhya.viswanathan at intel.com>; OpenJDK Security <security-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,
> 
> I did some performance testing on the changes and noticed that while the larger data sizes perform better, there is a drop in the smaller data sizes.  16byte data sizes saw a drop from 2.4m ops/sec to 1.7m ops/sec and 64bytes dropped from 2.1m ops/sec to 1.5m ops/sec.  At 256 bytes it is roughly equal.  At 16k is the best performance increase from 60k ops/sec to 130 ops/sec
> 
> Are the AVX instructions slower to setup and therefore affect smaller data sizes?  Or maybe the larger array allocation in GHASH.java?
> 
> Tony
> 
> On 11/29/18 12:08 PM, Anthony Scarpino wrote:
>> [removed core-libs, added security-dev]
>>
>> I'm fine with the jdk changes and solaris-sparc appears to work fine
>> with the existing security and intrinsic tests.  I do not feel
>> comfortable reviewing the hotspot changes, so either Vladimir or
>> someone else from the hotspot team would need to look at it.
>>
>> Tony
>>
>> On 11/20/18 6:45 PM, Kamath, Smita wrote:
>>> Hi Tony,
>>>
>>> Thanks for your comments.
>>>
>>> 1)  This intrinsic is also used with solaris-sparc, has there been a
>>> sanity check by anyone to make sure this does not break the sparc
>>> intrinsic? It may work as the code is now since the sparc intrinsic
>>> will only use the first two longs in the subkeyHtbl.
>>> Would it be possible to help with this sanity check?  I don't have
>>> the required set-up to test this scenario.
>>>
>>> 2) I have changed the code so that subkeyH corresponds to the first
>>> two entries of subkeyHtbl.  Please find the updated webrev link.
>>>
>>> Bug link: https://bugs.openjdk.java.net/browse/JDK-8214074
>>>
>>> Webrev link: http://cr.openjdk.java.net/~svkamath/ghash/webrev01/
>>>
>>> Thanks and Regards,
>>> Smita
>>>
>>>
>>>
>>> -----Original Message-----
>>> From: Anthony Scarpino [mailto:anthony.scarpino at oracle.com]
>>> Sent: Tuesday, November 20, 2018 2:05 PM
>>> To: Kamath, Smita <smita.kamath at intel.com>; 'Vladimir Kozlov'
>>> <vladimir.kozlov at oracle.com>
>>> Cc: Viswanathan, Sandhya <sandhya.viswanathan at intel.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
>>>
>>> On 11/19/18 12:50 PM, Kamath, Smita wrote:
>>>> Hi Vladimir,
>>>>
>>>> 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).
>>>>
>>>> I, smita.kamath at intel.com <mailto:smita.kamath at intel.com> , Shay
>>>> Gueuron, (shay.gueron at intel.com <mailto:shay.gueron at intel.com>)and
>>>> Regev Shemy (regev.shemy at intel.com <mailto:regev.shemy at intel.com>)
>>>> are contributors to this code.
>>>>
>>>> Link to Bug: https://bugs.openjdk.java.net/browse/JDK-8214074
>>>>
>>>> Link to webrev: http://cr.openjdk.java.net/~svkamath/ghash/webrev/
>>>>
>>>> For testing the implementation, I have executed TestAESMain.java. I
>>>> have executed Jtreg tests and tested this code on 64 bit Windows and
>>>> Linux platforms.
>>>>
>>>> Please review and let me know if you have any comments.
>>>>
>>>> Thanks and Regards,
>>>>
>>>> Smita
>>>>
>>>
>>> Hi,
>>>
>>> This intrinsic is also used with solaris-sparc, has there been a
>>> sanity check by anyone to make sure this does not break the sparc
>>> intrinsic?
>>> It may work as the code is now since the sparc intrinsic will only
>>> use the first two longs in the subkeyHtbl.
>>>
>>> In that same idea, have you consider combining the subkeyH to be the
>>> first two of subkeyHtbl for the non-avx operations?  It would
>>> eliminate an extra two longs per instance.
>>>
>>> Tony
>>>
>>
> 



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