RFR(S) JDK-8205528: Base64 Encode Algorithm using AVX512 Instructions

Tue Jun 26 19:53:49 UTC 2018

Hit build failure on Windows:

jib > 
t:/workspace/open/src/hotspot/cpu/x86/stubGenerator_x86_64.cpp(4556): 
error C2024: 'alignas' attribute applies to variables, data members and 
tag types only
jib > 
t:/workspace/open/src/hotspot/cpu/x86/stubGenerator_x86_64.cpp(4595): 
error C2024: 'alignas' attribute applies to variables, data members and 
tag types only
jib > 
t:/workspace/open/src/hotspot/cpu/x86/stubGenerator_x86_64.cpp(4634): 
error C2024: 'alignas' attribute applies to variables, data members and 
tag types only
jib > 
t:/workspace/open/src/hotspot/cpu/x86/stubGenerator_x86_64.cpp(4649): 
error C2024: 'alignas' attribute applies to variables, data members and 
tag types only
jib > 
t:/workspace/open/src/hotspot/cpu/x86/stubGenerator_x86_64.cpp(4664): 
error C2024: 'alignas' attribute applies to variables, data members and 
tag types only
jib > 
t:/workspace/open/src/hotspot/cpu/x86/stubGenerator_x86_64.cpp(4679): 
error C2024: 'alignas' attribute applies to variables, data members and 
tag types only
jib > 
t:/workspace/open/src/hotspot/cpu/x86/stubGenerator_x86_64.cpp(4693): 
error C2024: 'alignas' attribute applies to variables, data members and 
tag types only
jib > lib/CompileJvm.gmk:149: recipe for target 
'/cygdrive/t/workspace/build/windows-x64/hotspot/variant-server/libjvm/objs/stubGenerator_x86_64.obj' 
failed

Vladimir

On 6/26/18 11:48 AM, Vladimir Kozlov wrote:
> Yes, this looks good to me. Let me test it.
> 
> Thanks,
> Vladimir
> 
> On 6/25/18 10:25 PM, Kamath, Smita wrote:
>> Hi Vladimir,
>>
>> Please find the updated webrev link.
>>
>> Webrev Link: http://cr.openjdk.java.net/~srukmannagar/Base64/webrev.00/
>> Bug link: https://bugs.openjdk.java.net/browse/JDK-8205528
>>
>> Please let me know if you have additional questions.
>>
>> Thanks and Regards,
>> Smita
>>
>> -----Original Message-----
>> From: Vladimir Kozlov [mailto:vladimir.kozlov at oracle.com]
>> Sent: Monday, June 25, 2018 10:48 AM
>> To: Kamath, Smita <smita.kamath at intel.com>
>> Cc: hotspot compiler <hotspot-compiler-dev at openjdk.java.net>; 
>> core-libs-dev at openjdk.java.net; Paul Sandoz <paul.sandoz at oracle.com>
>> Subject: Re: RFR(S) JDK-8205528: Base64 Encode Algorithm using AVX512 
>> Instructions
>>
>> I forgot to reply to your answers.
>>
>> On 6/22/18 2:49 PM, Kamath, Smita wrote:
>>> Hi Vladimir,
>>>
>>> Please see my answers to your questions as below:
>>>
>>> 1) One question so: why you have own copy of base64 charsets and not 
>>> using one in library:
>>> I am using vpgatherdd instruction to fetch multiple values from 
>>> base64 array in a single instruction with a vector index. Vpgatherdd 
>>> instruction works on 32 bit array and so I need to define base64 
>>> charset in a 32 bit array. I have given reference to gather 
>>> instruction below.
>>
>> As was discussed in an other e-mail lets keep your copy.
>>
>>>
>>> 2) Some indents in new and old Assembler::emit_operand() are off. In 
>>> new Assembler::emit_operand() is better use } else { instead of 
>>> 'return' in one branch.
>>> I'll make the necessary changes and send an updated webrev.
>>>
>>> 3) This is first time I see that XMM register can be used for index 
>>> in address. Is it true? Can you point to Intel's document which 
>>> describes it.
>>> I am using vpgatherdd instruction which requires index vector with 
>>> scale. It uses VSIB addressing where the index register is a zmm 
>>> register.
>>> Please refer to reference manual, volume 2c, page 2211:
>>> https://software.intel.com/sites/default/files/managed/39/c5/325462-sd
>>> m-vol-1-2abcd-3abcd.pdf Also see, section 2.3.12, page 524 for VSIB
>>> memory addressing information.
>>
>> Got it. Thanks for document reference.
>>
>>>
>>> 4)  Please, add tests to 
>>> test/hotspot/jtreg/compiler/intrinsics/base64 (may be similar to sha 
>>> or AES in compiler/codegen/aes) to make sure that all flags, 
>>> intrinsic is used and it produces correct result.
>>> I will add test cases as per your suggestion.
>>
>> Thanks,
>> Vladimir
>>
>>>
>>> Please let me know if you have additional questions.
>>>
>>> Thanks,
>>> Smita
>>>
>>> -----Original Message-----
>>> From: Vladimir Kozlov [mailto:vladimir.kozlov at oracle.com]
>>> Sent: Friday, June 22, 2018 12:29 PM
>>> To: Kamath, Smita <smita.kamath at intel.com>
>>> Cc: hotspot compiler <hotspot-compiler-dev at openjdk.java.net>
>>> Subject: Re: RFR(S) JDK-8205528: Base64 Encode Algorithm using AVX512
>>> Instructions
>>>
>>> Hi Smita,
>>>
>>> I CCing to Libs to review code changes in Base64.java.
>>>
>>> Looks like you changed all need place to implement intrinsic.
>>> One question so: why you have own copy of base64 charsets and not 
>>> using one in library:
>>>
>>>             private int encode0(byte[] src, int off, int end, byte[] 
>>> dst) {
>>>                 char[] base64 = isURL ? toBase64URL : toBase64;
>>>
>>> Some indents in new and old Assembler::emit_operand() are off.
>>>
>>> In new Assembler::emit_operand() is better use } else { instead of 
>>> 'return' in one branch.
>>>
>>> This is first time I see that XMM register can be used for index in 
>>> address. Is it true? Can you point to Intel's document which 
>>> describes it.
>>>
>>> What testing you did?
>>>
>>> Please, add tests to test/hotspot/jtreg/compiler/intrinsics/base64 
>>> (may be similar to sha or AES in compiler/codegen/aes) to make sure 
>>> that all flags, intrinsic is used and it produces correct result.
>>>
>>> I know there is test/jdk/java/util/Base64/ tests but they may not 
>>> trigger intrinsic usage. But you can use them as starting point for 
>>> new tests.
>>>
>>> Thanks,
>>> Vladimir
>>>
>>> On 6/22/18 11:47 AM, Kamath, Smita wrote:
>>>> Hi Vladimir,
>>>>
>>>> I'd like to contribute an optimization for Base64 Encoding Algorithm
>>>> using AVX512 Instructions. This optimization shows 1.5x improvement
>>>> on
>>>> x86_64 platform(SKL).
>>>>
>>>> Link to Bug: https://bugs.openjdk.java.net/browse/JDK-8205528
>>>>
>>>> Link to webrev:
>>>> http://cr.openjdk.java.net/~vdeshpande/Base64/webrev.00/
>>>>
>>>> For testing the implementation, I have run tests under
>>>> test/jdk/java/util/Base64/ and also ran
>>>> test/jdk/com/sun/jndi/ldap/Base64Test.java
>>>>
>>>> I have also run jtreg.
>>>>
>>>> Please review and let me know if you have any comments.
>>>>
>>>> Thanks and Regards,
>>>>
>>>> Smita
>>>>