[HBASE-22670] JDK 11 and CellComparator

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 3.0.0-alpha-1
• Labels: jdk11
• Assignee: ramkrishna.s.vasudevan
• Reporter: ramkrishna.s.vasudevan
• Created: 10/Jul/19 09:35
• Updated: 30/Jan/20 06:13

Description

This could act as a parent JIRA for analysing JDK 11 and the Comparator impls that we have.
Latest JDK has support for SIMD and AVX512, which means it has support for vectorizations.
See JDK11's ArraysSupport#mismatch() and vectorizedMismatch().
We also have BufferMismatch#mismatch() which is not publicly exposed but it uses the ArraysSupport#vectorizedMismatch().
Internally vectorizedMismatch() does something similar to what UnsafeComparator#compareToUnsafe does. Will add about the details of the study in further comments.

The JDK also exposes new annotations like @HotSpotIntrinsicCandidate and @ForceInline tags that helps in inlining the intrinsic calls.