HBASE-28025 Enhance ByteBufferUtils.findCommonPrefix to compare 8 bytes each time

[jbewing]

What

This PR updates ByteBufferUtils#findCommonPrefix and Bytes#findCommonPrefix to compare 8 bytes from the input buffers/arrays if Unsafe access is available. On platforms where Unsafe is unavailable, we use the current implementations. This is a similar optimization as to what is already done with ByteBufferUtils#compareToUnsafe.

Implementation Notes

There was a Bytes#findCommonPrefix method and a ByteBufferUtils#findCommonPrefix method that both accepted byte[] args. I've updated the ByteBufferUtils#findCommonPrefix method to delegate to Bytes#findCommonPrefix and applied the optimization for 8 byte at a time comparison to the Bytes class.

Overall, the implementation draws a ton of inspiration from ByteBufferUtils#compareToUnsafe. The only large change that I made is for how we handle mismatches in the big endian case. I used the number of leading zeros intrinsic there instead of the number of trailing zeros intrinsic to find which byte was mismatched.

Testing

I've added some unit tests to cover testing the path with unsafe enabled and disabled.

Benchmarking

I haven't done any micro-benchmarking of the new "faster" implementations vs. the current implementations. I'll update the JIRA with a link to those when I get a chance to write them. For now, I'm assuming that this method of finding common prefixes is faster than the current one based off the previous micro-benchmarking results for compareTo (as this is very similar code). I've done some microbenchmarking with JMH. The results are in this JIRA comment

HBASE-28025

[Apache-HBase]

🎊 +1 overall

Vote	Subsystem	Runtime	Comment
+0 🆗	reexec	0m 13s	Docker mode activated.
-0 ⚠️	yetus	0m 2s	Unprocessed flag(s): --brief-report-file --spotbugs-strict-precheck --whitespace-eol-ignore-list --whitespace-tabs-ignore-list --quick-hadoopcheck
		_ Prechecks _
		_ master Compile Tests _
+1 💚	mvninstall	2m 28s	master passed
+1 💚	compile	0m 16s	master passed
+1 💚	shadedjars	4m 31s	branch has no errors when building our shaded downstream artifacts.
+1 💚	javadoc	0m 16s	master passed
		_ Patch Compile Tests _
+1 💚	mvninstall	2m 18s	the patch passed
+1 💚	compile	0m 17s	the patch passed
+1 💚	javac	0m 17s	the patch passed
+1 💚	shadedjars	4m 29s	patch has no errors when building our shaded downstream artifacts.
+1 💚	javadoc	0m 14s	the patch passed
		_ Other Tests _
+1 💚	unit	1m 44s	hbase-common in the patch passed.
		18m 10s

Subsystem	Report/Notes
Docker	ClientAPI=1.43 ServerAPI=1.43 base: https://ci-hbase.apache.org/job/HBase-PreCommit-GitHub-PR/job/PR-5354/1/artifact/yetus-jdk8-hadoop3-check/output/Dockerfile
GITHUB PR	#5354
Optional Tests	javac javadoc unit shadedjars compile
uname	Linux d48a3a195633 5.4.0-156-generic #173-Ubuntu SMP Tue Jul 11 07:25:22 UTC 2023 x86_64 x86_64 x86_64 GNU/Linux
Build tool	maven
Personality	dev-support/hbase-personality.sh
git revision	master / 2fb2ae1
Default Java	Temurin-1.8.0_352-b08
Test Results	https://ci-hbase.apache.org/job/HBase-PreCommit-GitHub-PR/job/PR-5354/1/testReport/
Max. process+thread count	354 (vs. ulimit of 30000)
modules	C: hbase-common U: hbase-common
Console output	https://ci-hbase.apache.org/job/HBase-PreCommit-GitHub-PR/job/PR-5354/1/console
versions	git=2.34.1 maven=3.8.6
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[Apache-HBase]

🎊 +1 overall

Vote	Subsystem	Runtime	Comment
+0 🆗	reexec	0m 24s	Docker mode activated.
-0 ⚠️	yetus	0m 3s	Unprocessed flag(s): --brief-report-file --spotbugs-strict-precheck --whitespace-eol-ignore-list --whitespace-tabs-ignore-list --quick-hadoopcheck
		_ Prechecks _
		_ master Compile Tests _
+1 💚	mvninstall	2m 54s	master passed
+1 💚	compile	0m 15s	master passed
+1 💚	shadedjars	4m 58s	branch has no errors when building our shaded downstream artifacts.
+1 💚	javadoc	0m 15s	master passed
		_ Patch Compile Tests _
+1 💚	mvninstall	2m 37s	the patch passed
+1 💚	compile	0m 15s	the patch passed
+1 💚	javac	0m 15s	the patch passed
+1 💚	shadedjars	4m 56s	patch has no errors when building our shaded downstream artifacts.
+1 💚	javadoc	0m 13s	the patch passed
		_ Other Tests _
+1 💚	unit	2m 7s	hbase-common in the patch passed.
		20m 21s

Subsystem	Report/Notes
Docker	ClientAPI=1.43 ServerAPI=1.43 base: https://ci-hbase.apache.org/job/HBase-PreCommit-GitHub-PR/job/PR-5354/1/artifact/yetus-jdk11-hadoop3-check/output/Dockerfile
GITHUB PR	#5354
Optional Tests	javac javadoc unit shadedjars compile
uname	Linux b693bd2ca6af 5.4.0-1103-aws #111~18.04.1-Ubuntu SMP Tue May 23 20:04:10 UTC 2023 x86_64 x86_64 x86_64 GNU/Linux
Build tool	maven
Personality	dev-support/hbase-personality.sh
git revision	master / 2fb2ae1
Default Java	Eclipse Adoptium-11.0.17+8
Test Results	https://ci-hbase.apache.org/job/HBase-PreCommit-GitHub-PR/job/PR-5354/1/testReport/
Max. process+thread count	396 (vs. ulimit of 30000)
modules	C: hbase-common U: hbase-common
Console output	https://ci-hbase.apache.org/job/HBase-PreCommit-GitHub-PR/job/PR-5354/1/console
versions	git=2.34.1 maven=3.8.6
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[Apache-HBase]

🎊 +1 overall

Vote	Subsystem	Runtime	Comment
+0 🆗	reexec	0m 42s	Docker mode activated.
		_ Prechecks _
+1 💚	dupname	0m 0s	No case conflicting files found.
+1 💚	hbaseanti	0m 0s	Patch does not have any anti-patterns.
+1 💚	@author	0m 0s	The patch does not contain any @author tags.
		_ master Compile Tests _
+1 💚	mvninstall	3m 0s	master passed
+1 💚	compile	0m 36s	master passed
+1 💚	checkstyle	0m 17s	master passed
+1 💚	spotless	0m 44s	branch has no errors when running spotless:check.
+1 💚	spotbugs	0m 34s	master passed
		_ Patch Compile Tests _
+1 💚	mvninstall	2m 37s	the patch passed
+1 💚	compile	0m 34s	the patch passed
-0 ⚠️	javac	0m 34s	hbase-common generated 2 new + 34 unchanged - 0 fixed = 36 total (was 34)
+1 💚	checkstyle	0m 13s	the patch passed
+1 💚	whitespace	0m 0s	The patch has no whitespace issues.
+1 💚	hadoopcheck	9m 14s	Patch does not cause any errors with Hadoop 3.2.4 3.3.5.
+1 💚	spotless	0m 41s	patch has no errors when running spotless:check.
+1 💚	spotbugs	0m 39s	the patch passed
		_ Other Tests _
+1 💚	asflicense	0m 12s	The patch does not generate ASF License warnings.
		25m 56s

Subsystem	Report/Notes
Docker	ClientAPI=1.43 ServerAPI=1.43 base: https://ci-hbase.apache.org/job/HBase-PreCommit-GitHub-PR/job/PR-5354/1/artifact/yetus-general-check/output/Dockerfile
GITHUB PR	#5354
Optional Tests	dupname asflicense javac spotbugs hadoopcheck hbaseanti spotless checkstyle compile
uname	Linux f007f107ca19 5.4.0-156-generic #173-Ubuntu SMP Tue Jul 11 07:25:22 UTC 2023 x86_64 x86_64 x86_64 GNU/Linux
Build tool	maven
Personality	dev-support/hbase-personality.sh
git revision	master / 2fb2ae1
Default Java	Eclipse Adoptium-11.0.17+8
javac	https://ci-hbase.apache.org/job/HBase-PreCommit-GitHub-PR/job/PR-5354/1/artifact/yetus-general-check/output/diff-compile-javac-hbase-common.txt
Max. process+thread count	78 (vs. ulimit of 30000)
modules	C: hbase-common U: hbase-common
Console output	https://ci-hbase.apache.org/job/HBase-PreCommit-GitHub-PR/job/PR-5354/1/console
versions	git=2.34.1 maven=3.8.6 spotbugs=4.7.3
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