Enable JFR continuous profiling with default setting

[ahamlat]

PR description

Enable JFR continuous profiling with default setting.
Java Flight Recorder (JFR) serves as an integrated mechanism within the Java Virtual Machine (JVM) for gathering, analyzing, and profiling information regarding the performance and memory usage of Java applications. Its design ensures minimal impact on performance, making it suitable for deployment in high-demand production settings.
With default setting, the impact on performance is less than 1 %.

Once the recording in place, we can either dump the recording from the last restart knowing that the recording is limited to 250 MiB, or start a second recording to have a recording you small set of data and in a controlled period.

Configure the recording with default setting profile
BESU_OPTS=-XX:StartFlightRecording,dumponexit=true,settings=default.jfc

Check the recording
sudo jcmd PID JFR.check

Start a parallel recording
sudo jcmd PID JFR.start

Dump the profiling to a file
Dump the default recording : sudo jcmd PID JFR.dump name=1 filename=FILEPATH
Dump the parallel recording : sudo jcmd PID JFR.dump name=2 filename=FILEPATH

Fixed Issue(s)

#6957

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Locally, you can run these tests to catch failures early:

• unit tests: ./gradlew build
• acceptance tests: ./gradlew acceptanceTest
• integration tests: ./gradlew integrationTest
• reference tests: ./gradlew ethereum:referenceTests:referenceTests

[ahamlat]

Sharing some tests here :

ahamlat@dev-elc-besu-***:/opt/besu/besu-with-profiling$ sudo jcmd 433466 JFR.check
433466:
Recording 1: name=1 maxsize=250.0MB (running)

ahamlat@dev-elc-besu-***:/opt/besu/besu-with-profiling$ sudo jcmd 433466 JFR.dump name=1 filename=/tmp/recording.jfr
433466:
Dumped recording "1", 4.2 MB written to:

/tmp/recording.jfr

ahamlat@dev-elc-besu-***:/opt/besu/besu-with-profiling$ sudo jcmd 433466 JFR.start
433466:
Started recording 2. No limit specified, using maxsize=250MB as default.

Use jcmd 433466 JFR.dump name=2 filename=FILEPATH to copy recording data to file.

ahamlat@dev-elc-besu-***:/opt/besu/besu-with-profiling$ sudo jcmd 433466 JFR.check
433466:
Recording 1: name=1 maxsize=250.0MB (running)

Recording 2: name=2 maxsize=250.0MB (running)

ahamlat@dev-elc-besu-***:/opt/besu/besu-with-profiling$ sudo jcmd 433466 JFR.dump name=2 filename=/tmp/recording2.jfr
433466:
Dumped recording "2", 2.0 MB written to:

/tmp/recording2.jfr

[ahamlat]

There is still one small issue that happens with java 17, but not with java 21. The JVM displays in the output dumponexit=true,settings=default.jfc which is not great in terms of user experience, when for example we want to display Besu version :

bin/besu --version
dumponexit=true,settings=default.jfc
besu/v24.5-develop-c6c6dab/linux-x86_64/openjdk-java-17

This is actually what is making some of the acceptance tests fail, ex. besu --help command test

[ahamlat]

It is simple to reproduce even with only Java --version

Java 17

java -XX:StartFlightRecording -Xlog:jfr*=off -version
dumponexit=false
openjdk version "17.0.10" 2024-01-16
OpenJDK Runtime Environment (build 17.0.10+7-Ubuntu-122.04.1)
OpenJDK 64-Bit Server VM (build 17.0.10+7-Ubuntu-122.04.1, mixed mode, sharing)

Java 21

java -XX:StartFlightRecording -Xlog:jfr*=off -version
openjdk version "21.0.2" 2024-01-16
OpenJDK Runtime Environment (build 21.0.2+13-Ubuntu-122.04.1)
OpenJDK 64-Bit Server VM (build 21.0.2+13-Ubuntu-122.04.1, mixed mode, sharing)

[ahamlat]

As Java 21 is now needed to build and run Besu : #7177, we can move on on this PR and enable continuous profiling.

[ahamlat]

Java 21 has JFR included by default, but the main benefit from this PR is to have the profiling enabled from the last restart. This will help to troubleshoot an issue that happened that we can not reproduce.
Without this PR, we can start a new JFR recording but we don't have access to a recording from the last restart.