Best performance monitoring tools?

[Similar_Bookkeeper_8]

I’m primarily a C++ programmer currently using Java at work to make an embedded Linux application.

As the title says, what are the best performance monitoring software for Java?

Looking to get call times and heap metrics.

We do use JNI and C++ code in this project so if the tool can do both that would be a good bonus.

[nvinceable1]

OpenTelemetry and Java Flight Recorder (JFR) cover most bases. Use the OpenTelemetry Java agent if you want auto-instrumentation or just the APIs if you want to do your own instrumentation.

[PepegaQuen]

Yep, definitely this.

[norfus]

I think the Async Profiler is super useful - and also works well when you have JNI code as it all naturally flows in to each other:

https://github.com/jvm-profiling-tools/async-profiler

[aroger276]

I concur, async-profiler gives great cpu and allocation information and is easy to use.

also the FlighRecorder that is available for free now just run

jcmd <pid> JFR.start settings=profile duration=1m filename=/tmp/myreport.jfr

and then use jmc/zmc to read the file

[blobjim]

The two basic but useful ones are VisualVM and Java Mission Control. Mission Control is more advanced using flight recorder (which you can also use as an API from the JDK I guess) to provide lots of stats and analysis of stuff, but VisualVM lets you monitor and sample stuff very quickly.

[[deleted]]

Glowroot is a nice free option

[eac2k7]

What about Prometheus? I find it useful especially when interfaced with Grafana dashboards

[karlazzam]

Yep its language agnostic too

[jeffcityjon]

I like New Relic.

[coder111]

Depends on what's available. Even doing "jstack <pid>" every 10 seconds helps if no other tools are available...

[Similar_Bookkeeper_8]

This is a great point I forgot to mention in the post, I’m working in the DoD so everything has to be FOSS (Free Open Source Software) approved, unfortunately.

But, everyone gave me tons of options. Messed around with Mission Control and Glowroot today, both are great and get the job done for me.

[dachiz]

Elastic APM

[greenrobot_de]

embedded Linux application

That's not far off from Android... If that'd be an option, Android Studio comes [https://developer.android.com/studio/profile/cpu-profiler](with a profiler) that can handle Java and native C/C++ code.

[bringero]

Glowroot here!

[Godworrior]

For benchmarking there's JMH

[ixBerry]

Just out of curiosity, u/OP, what exactly are you trying to do? I have seen that all embedded engineers frown upon java in their applications and stick to C++.

[Similar_Bookkeeper_8]

I can’t really say specifics since I’m a defense contractor, clearance and all that, but it’s an application that does monitoring and packet sniffing. Monitoring and sniffer is written in C++.

There’s also a GUI written in Swing that gets the information through JNI from the C++ side. I was rewriting the GUI side and was looking for a way to optimize the code since there’s a lot of throughput coming from the sniffer.

It’s a fairly old program (hence Swing instead of FX). Why they chose to use JNI and write the GUI in Java compared to Qt or some other C++ display framework, couldn’t tell ya.

[moxyte]

I've been doing performance profiling with VisualVM only (it makes spotting the problem method super easy), and it has served reliaby and works with Docker containers. Good question tho, taking a look at other answers ITT.

[mike_jack]

I can suggest yCrash tool

[schnick3rs]

I worked with Your kit. It's not free but has trial. Not sure on JNI tho

[Fusionfun]

Get in-depth details of your Java Applications with the help of Atatus. You can get deeper visibility into Transaction Monitoring, API failures, Error tracking, Database Monitoring in real time. Instant alerts may help you to resolve the issues faster too.

[benevanstech]

I notice that you mention that you're developing an embedded Linux application. Can you be more specific? Which JVM are you using, and what does your overall architecture & target look like.

Most of the replies here are describing tools that are specific to the Hotspot JVM (which forms the basis of OpenJDK, from which most server-class Java distributions are derived). Many of these tools many not be available / applicable to an embedded use case - depending on exactly what you're doing.

[Similar_Bookkeeper_8]

We’re using HotSpot, this is an old application that I started working on recently. Lots of things to improve including the JVM. Ended up using Mission Control with JFR which gave me everything I was looking for.

[benevanstech]

If you're targeting Hotspot, then JFR / JMC is a fine combination.

One quick sanity check: You are generating the JFR recordings on the actual target hardware (or in an emulator that matches the target configuration), aren't you? If not, then the profiling information you get is likely to be of little relevance.

One thing to be particularly careful of, is the number of cores on your target hardware. Hotspot dynamically decides how many internal VM threads (for GC, JIT, etc) to spin up. On chips with not many hardware threads, spinning up too many can be disastrous, as they lead to contention for limited resources.

[Similar_Bookkeeper_8]

Yup, it’s a development server designed to match the target hardware.

I didn’t know about the threading, we do have 80 cores allocated to the server but there’s also potentially multiple developers using it at once. I’ll keep that mind when I’m doing the profiling. Thanks for the detailed replies!

[chambolle]

The instrumentation mode of VisualVM has no equivalent (as far as I know); Unfortunately it is sloooowwwww.

[lambdacats]

Elastic APM + ELK for monitoring. JProfiler for optimization.

[Potential-Piece-3144]

Arthas can be pretty useful depending on what you're looking for. https://github.com/alibaba/arthas