[10] RFR (S): 8189177 - AARCH64: Improve _updateBytesCRC32C intrinsic

[Dmitry Samersoff]

Dmitry,

Looks good to me.

-Dmitry


On 11/08/2017 01:34 AM, White, Derek wrote:
> Hi Dmitry,
> 
> This looks good!
> 
> Thanks,
> 
>  - Derek
> 
>> -----Original Message-----
>> From: hotspot-compiler-dev [mailto:hotspot-compiler-dev-
>> bounces at openjdk.java.net] On Behalf Of Dmitry Chuyko
>> Sent: Thursday, November 02, 2017 5:07 PM
>> To: hotspot-compiler-dev at openjdk.java.net
>> Subject: Re: [10] RFR (S): 8189177 - AARCH64: Improve _updateBytesCRC32C
>> intrinsic
>>
>> Similar to CRC32 I added private
>> MacroAssembler::kernel_crc32c_using_crc32c().
>>
>> webrev: http://cr.openjdk.java.net/~dchuyko/8189177/webrev.01/
>>
>> -Dmitry
>>
>>
>> On 10/20/2017 08:45 PM, Dmitry Chuyko wrote:
>>> Hello,
>>>
>>> Please review an improvement of CRC32C calculation on AArch64. It is
>>> done pretty similar to a change for JDK-8189176 described in [1].
>>>
>>> MacroAssembler::kernel_crc32c gets unused table registers. They can be
>>> used to make neighbor loads and CRC calculations independent. Adding
>>> prologue and epilogue for main by-64 loop makes it applicable starting
>>> from len=128 so additional by-32 loop is added for smaller lengths.
>>>
>>> rfe: https://bugs.openjdk.java.net/browse/JDK-8189177
>>> webrev: http://cr.openjdk.java.net/~dchuyko/8189177/webrev.00/
>>> benchmark:
>>> http://cr.openjdk.java.net/~dchuyko/8189177/crc32c/CRC32CBench.java
>>>
>>> Results for T88 and A53 [2] are similar to CRC32 change (good), but
>>> again splitting pair loads may slow down other CPUs so measurements on
>>> different HW are welcome.
>>>
>>> -Dmitry
>>>
>>> [1]
>>> http://mail.openjdk.java.net/pipermail/hotspot-compiler-dev/2017-Octob
>>> er/027225.html
>>> [2]
>>> https://bugs.openjdk.java.net/browse/JDK-
>> 8189177?focusedCommentId=1412
>>> 4535&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-
>> tabpanel#comment-14124535
>>>
>