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

[Lindenmaier, Goetz]

Hi Martin, 

well, I like math, but not if it's expressed in Power vector instructions :)
I had a look at the code and checked our nightly tests where you put
the change to make sure they are fine. No issues. Eventually you could
put it into the jdk build, too, then it's also verified by the benchmarks.
I understand you are now generating the tables at startup. 

Looks good.

Best regards,
   Goetz.

> -----Original Message-----
> From: Doerr, Martin
> Sent: Donnerstag, 1. März 2018 16:50
> 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>
> 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 :))
> 
> 
> 
> Best regards,
> 
> Martin
> 
>