JVM Profiling Follow ups

[adinauer]

Description

We have released JVM Profiling in https://github.com/getsentry/sentry-java/releases/tag/8.23.0

There are still tasks /improvements we could do:

• Docs
• Release registry entries
• Add module to .craft.yml
• Verify caching behaviour of ServiceLoader is not an issue (i.e. does not cause a large overhead on each chunk) - otherwise cache
• Remove / reduce vendored code and replace what's possible with JFR converter, also see Expose a dictionary of javaThreads from JfrReader async-profiler/async-profiler#1525
• Upgrade async-profiler to 4.1+ to support newer Java Versions (23+); there are issues with a Converter dictionary
• Log a specific message why Profiling isn't enabled if the wrong config property for setting sample rate is used (profiles-sample-rate) on JVM
• Enable / showcase Profiling in (more of) our samples
• Allow configuring profilingTracesHz via sentry.properties (ExternalOptions)
• Add a .cursor rules file to explain how Profiling works
• We could reduce profile chunk size / duration based on thread count of the application. This could help in case profiles are dropped due to being too large. Thread.activeCount() or ThreadMXBean (more accurate)
• Continuous Profiling could upload JFR files #4768 (we should wait for feedback first, maybe we don't need this)
• JVM Profiling Windows support #4779
• Detect that async-profiler is the (major) version we expect on startup, crash otherwise

[linear]

JAVA-194

[joaocanaverde-blue]

@adinauer great news on this being released!

Appreciate it's early days for this feature, but wanted to ask if there any environments where profiling is not expected to work yet?

Haven't had a chance to do much troubleshooting yet (would need to spin it up again and grab the log file/core dump), but tried enabling profiling and it caused a crash.

Running on ECS Fargate on an arm64 instance. It's a Spring Boot app written in Kotlin.

Maybe it's not compatible with arm64? Or Kotlin?

Relevant startup logs:

DEBUG: Started Profiler.
A fatal error has been detected by the Java Runtime Environment:
SIGSEGV (0xb) at pc=0x0000000000000000, pid=1, tid=203
JRE version: OpenJDK Runtime Environment Corretto-24.0.2.12.1 (24.0.2+12) (build 24.0.2+12-FR)
Java VM: OpenJDK 64-Bit Server VM Corretto-24.0.2.12.1 (24.0.2+12-FR, mixed mode, sharing, tiered, compressed class ptrs, z gc, linux-aarch64)
Problematic frame:
C [libasyncProfiler-1255257512175285949.so+0x1f990]
Core dump will be written. Default location: //core.1
An error report file with more information is saved as:
//hs_err_pid1.log
The crash happened outside the Java Virtual Machine in native code.
See problematic frame for where to report the bug.
If you would like to submit a bug report, please visit:
https://github.com/corretto/corretto-24/issues/

Thanks in advance!

[lcian]

Hey @joaocanaverde-blue! Thanks for reaching out and wanting to try profiling.
It's known that the async-profiler library on version 3.0 (which is the one we're using at the moment for our profiling feature) segfaults on JDK 23 and later, so that's what's happening in your case.
As you can see in the list of follow-ups, we have an item to upgrade to the newest version of the library.

[joaocanaverde-blue]

Hey @joaocanaverde-blue! Thanks for reaching out and wanting to try profiling. It's known that the async-profiler library on version 3.0 (which is the one we're using at the moment for our profiling feature) segfaults on JDK 23 and later, so that's what's happening in your case. As you can see in the list of follow-ups, we have an item to upgrade to the newest version of the library.

@lcian I see, missed that one. Thanks!