hotspot | The Linux perf GUI for performance analysis | Monitoring library

You need to setup JAVA_HOME and SPARK_DIST_CLASSPATH as well. You can download Hadoop from the main website https://hadoop.apache.org/releases.html

Those samples depend on JDK internals.

Looks like since JDK 9 and JDK-8152907, Math.log is no longer intrinsified into C2 intermediate representation. Instead, a direct call to a quick LIBM-backed stub is made. This is usually faster for the code that actually uses the result. Notice how measureCorrect is faster in JDK 17 output in your case.

But for JMH samples, it limits the the compiler optimizations around the Math.log, and dead code / folding samples do not work properly. The fix it to make samples that do not rely on JDK internals without a good reason, and instead use a custom written payload.

This is being done in JMH here:

• https://bugs.openjdk.java.net/browse/CODETOOLS-7903094
• https://github.com/openjdk/jmh/pull/60

Accessing the command-line arguments like that is no longer supported in Scala 3:

https://docs.scala-lang.org/scala3/reference/dropped-features/delayed-init.html

JIT compilation in HotSpot JVM is 1) based on runtime profile data; 2) uses speculative optimizations.

Once the method is compiled at the maximum optimization level, HotSpot stops profiling this code, so it is never recompiled afterwards, no matter how long the code runs. (The exception is when the method needs to be deoptimized or unloaded, but it's not your case).

In the first case (SELECT_QUICK == true), the condition remaining > fBuffer1.length - fIdx is never met, and HotSpot JVM is aware of that from profiling data collected at lower tiers. So it speculatively hoists the check out of the loop, and compiles the loop body with the assumption that array index is always within bounds. After the optimization, the loop is compiled like this (in pseudocode):

To measure the branch you are interested in and particularly the scenario when while loop becomes hot, I've used the following benchmark:

Make sure of your JAVA_HOME Path in your terminal with

I am missing the jmods directory in my jdk. On Fedora jmods are a separate install https://fedora.pkgs.org/35/fedora-x86_64/java-11-openjdk-jmods-11.0.12.0.7-4.fc35.x86_64.rpm.html

Run sudo dnf install java-11-openjdk-jmods

This is what solved it for me on my M1.

1. Go to Android Studio Preview and download the latest Canary build for Apple chip (Chipmunk). Don't worry this is just to get through the initial setup.
2. Unpack it, run it, let it install all the SDK components, accept licenses, etc as usual.
3. Once it's done, simply close it and delete it.

Now when you start your stable Android Studio (Arctic Fox) you should not see the error.

Based on the various comments ...

1. You have Java 17 installed ... manually ... in /opt/jdk17
2. You have JAVA_HOME pointing on the base of the Java 17 installation. I assume that there is (for example) a /opt/jdk17/bin/java executable.
3. The Java 17 installation directory is NOT on the command search path (PATH).
4. The search path is finding /usr/bin/java ... which (in your case) says Java 16 when you run java -version.
5. Your system has the "/etc/alternatives" system installed, but sudo update-alternatives --config java says that only Java 16 is available.

So ...

The "alternatives" mechanism creates and maintains symlinks to various switchable commands. If you run ls -l /usr/bin/java for example, I expect that you will see that it is a symlink. When you run update-alternatives, it will attempt to update the symlinks. But it can only do this for commands and command versions that it knows about.

Right now ... update-alternatives does not know about Java 17. It doesn't know it is installed, or where it is installed.

If you had installed Java 17 from the package manager, then the config files that tell update-alternatives about Java 17 would have been added too.

Solutions, ordered from "best" (1) to "worst".

1. Remove your manual install of Java 17 and install it from the package manager. You might need to find / add an "experimental" Debian package repo to do this. (I get the impression that the official Debian repo managers tend to be rather slow in picking up new stuff.)

2. Carefully read the documentation in man 1 update-alternatives and update-alternatives --help and then use the --install and --slave commands to tell it about Java 17.

3. Find the Java symlinks and manually replace them with symlinks to the Java 17 versions of the executables. (Be careful ...)

4. Add /opt/jdk17/bin to the start of your PATH. (Be careful ...)

5. Just use the full pathnames; e.g. /opt/jdk17/bin/java rather than java.

I also came across this:

• Java 17 on the Raspberry Pi which includes (among other things) example commands for adding Java 17 to the alternatives system. It also mentions using sdkman.

• How to Install Java 17 (JDK 17) on Debian 11. There is a comment that says:

  "Awesome! Thanks. This Debian package works on Raspberry Pi's Raspian 64-bit Bullseye as of posting. Only method that works without manually downloading packages and attempting to install. :)".

  But I see that you have a 32-bit Raspberry Pi ...