RFR(L): 8198894: [PPC64] More generic vector CRC implementation

[Michihiro Horie]

Hi Martin,

I double checked performance with our micro benchmark.
This change was 5 times faster. In addition, I did not observe degradation
with smaller length but have almost equal performance.

Best regards,
--
Michihiro,
IBM Research - Tokyo



From:	"Doerr, Martin" <martin.doerr at sap.com>
To:	"'hotspot-compiler-dev at openjdk.java.net'"
            <hotspot-compiler-dev at openjdk.java.net>
Cc:	"Lindenmaier, Goetz" <goetz.lindenmaier at sap.com>, "Hiroshi H
            Horii (HORII at jp.ibm.com)" <HORII at jp.ibm.com>, "Michihiro Horie
            (HORIE at jp.ibm.com)" <HORIE at jp.ibm.com>, Gustavo Romero
            <gromero at linux.vnet.ibm.com>
Date:	2018/03/02 00:49
Subject:	RFR(L): 8198894: [PPC64] More generic vector CRC implementation



Hi,

I have implemented a more generic version of the vector instruction based
CRC code.
It supports CRC32C and Big Endian, too.

The peak performance was even better for large input streams. I got almost
40GB/s.
Some smaller length may be slower than with the old version.
Maybe somebody from IBM would like to double-check performance.

Please review:
http://cr.openjdk.java.net/~mdoerr/8198894_PPC64_CRC32/webrev.00/
(hoping you like math J)

Best regards,
Martin

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