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

[Doerr, Martin]

Hi Michihiro and Götz,

thanks, Götz, for reviewing.

Michihiro, can I add you as 2nd reviewer (no need to be jdk-reviewer for that)? I think you have taken a look and you obviously ran tests. So if you're ok with the change, I can push it next week.

Our nightly tests look good, too.

Thanks and best regards,
Martin


From: Michihiro Horie [mailto:HORIE at jp.ibm.com]
Sent: Freitag, 2. März 2018 11:55
To: Doerr, Martin <martin.doerr at sap.com>
Cc: Lindenmaier, Goetz <goetz.lindenmaier at sap.com>; Gustavo Romero <gromero at linux.vnet.ibm.com>; Hiroshi H Horii (HORII at jp.ibm.com) <HORII at jp.ibm.com>; 'hotspot-compiler-dev at openjdk.java.net' <hotspot-compiler-dev at openjdk.java.net>
Subject: Re: RFR(L): 8198894: [PPC64] More generic vector CRC implementation


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

[Inactive hide details for "Doerr, Martin" ---2018/03/02 00:49:56---Hi, I have implemented a more generic version of the vector]"Doerr, Martin" ---2018/03/02 00:49:56---Hi, I have implemented a more generic version of the vector instruction based CRC code.

From: "Doerr, Martin" <martin.doerr at sap.com<mailto:martin.doerr at sap.com>>
To: "'hotspot-compiler-dev at openjdk.java.net'" <hotspot-compiler-dev at openjdk.java.net<mailto:hotspot-compiler-dev at openjdk.java.net>>
Cc: "Lindenmaier, Goetz" <goetz.lindenmaier at sap.com<mailto:goetz.lindenmaier at sap.com>>, "Hiroshi H Horii (HORII at jp.ibm.com<mailto:HORII at jp.ibm.com>)" <HORII at jp.ibm.com<mailto:HORII at jp.ibm.com>>, "Michihiro Horie (HORIE at jp.ibm.com<mailto:HORIE at jp.ibm.com>)" <HORIE at jp.ibm.com<mailto:HORIE at jp.ibm.com>>, Gustavo Romero <gromero at linux.vnet.ibm.com<mailto: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/<https://urldefense.proofpoint.com/v2/url?u=http-3A__cr.openjdk.java.net_-7Emdoerr_8198894-5FPPC64-5FCRC32_webrev.00_&d=DwMFAg&c=jf_iaSHvJObTbx-siA1ZOg&r=oecsIpYF-cifqq2i1JEH0Q&m=XoFQj6pl5KM4yrslTVuMvukjPfiyiw1vyK-FHCveKpc&s=VBCFi423koKhU902olYdRrAWTLdINLCJg_2BNXKfysE&e=>
(hoping you like math :))

Best regards,
Martin

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