RFR(L): 8189793: [s390]: Improve String compress/inflate by exploiting vector instructions

Schmidt, Lutz lutz.schmidt at sap.com
Wed Oct 25 10:01:41 UTC 2017

Dear all,

I would like to request reviews for this s390-only enhancement:

Bug:    https://bugs.openjdk.java.net/browse/JDK-8189793
Webrev: http://cr.openjdk.java.net/~lucy/webrevs/8189793.00/index.html

Vector instructions, which have been available on System z for a while (since z13), promise noticeable performance improvements. This enhancement improves the String Compress and String Inflate intrinsics by exploiting vector instructions, when available. For long strings, up to 2x performance improvement has been observed in micro-benchmarks.

Special care was taken to preserve good performance for short strings. All examined workloads showed a high ratio of short and very short strings.

Thank you!

Dr. Lutz Schmidt | SAP JVM | PI  SAP CP Core | T: +49 (6227) 7-42834

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