JProfiler Get rid of your performance problems and memory leaks! Modern Garbage Collection Tuning Java Performance Training Courses COURSES AVAILABLE NOW. We can provide training courses to handle all your Java performance needs Java Performance Tuning, 2nd ed The classic and most comprehensive book on tuning Java Java Performance Tuning Newsletter Your source of Java performance news. Subscribe now! Enter email: Training online Threading Essentials course JProfiler Get rid of your performance problems and memory leaks!

Back to newsletter 206 contents

It seems like we are now into a phase of growing diversity for mainstream JVMs. There was another period years ago when it seemed that the available mainstream JVMs were expanding. We had JRockit and Sun JVMs competing, alongside the IBM JVM; Waratek brought out a multi-tenancy JVM targeted at the cloud; and Excelsior was present along with Microsoft and HP all having their own JVMs, not to mention the GCJ attempt and a few experimental ones from academia as well as the Sun real-time JVM and the GemStone distributed JVM (with software transactional memory)!

Then we went through a period of JVM consolidation, divestment and plain neglect. But looking at the mainstream JVMs we have now, it feels, at least to me, like it's under more active development than ever before. Oracle of course has consolidated JRockit into HotSpot and that is now the HotSpot JVM. But additionally it's now almost completely open sourced, there is now the OpenJDK JVM which Oracle HotSpot is based on, with additional features like Mission Control - which is due to become open sourced too! Then Oracle has decided to create yet another JVM, the GraalVM for all their more interesting future enhancements.

Other vendors have also been active: Azul; IBM has open sourced their JVM with the Eclipse OpenJ9 JVM (see the talk listed in the articles below); and we still have Excelsior JET keeping up with Java developments. Of course we still have many other experimental and niche JVMs, but what's interesting is the mainstream space and that looks much more exciting than it has for years. Which means we performance engineers have more options to try - exciting times!

Now on to our usual links to articles, tools, news, talks, blogs. And if you need the tips from this month's articles and talks, as ever they are extracted into this month's tips page.

A note from this newsletter's sponsor

News

Java performance tuning related news.

• Making all fields volatile provides sequential consistency, but (or 'just' depending on how you see it) with an additional overhead of 10%-30% (which is less than assumed); by targeting which fields are not volatile, you can reduce that overhead significantly
• Benchmark of string replace, not relevant for Java 9+ but nice detail

Tools

Java performance tuning related tools.

• Lightweight JVM Diagnostics Tools and Containers: hsperfdata_$UID/$PID data (used by jstat, jps, jinfo); JVM attach; Serviceability Agent; JVMTI; JMX, etc
• Java Monitoring APIs and Java Management APIs
• IBM Garbage Collection and Memory Visualizer (GCMV) tool is used primarily to analyze Java memory usage. It is built by the IBM Java team and fully supported, and parses both IBM Java and Oracle Java verbose garbage collection log files
• IBM Thread and Monitor Dump Analyzer (TMDA) tool analyzes IBM and Oracle thread dumps, extracting out thread stacks and monitors and displaying them in a GUI

Articles

• Performance beyond Throughput: An OpenJ9 Case Study (Marius Pirvu/QCon)
• Java 9 VarHandles Best practices, and why? (Tobi Ajila/Devoxx)
• An Introduction to JVM Performance (Rafael Winterhalter/Devoxx)
• Memory Leaks: Fallacies and Misconceptions (Vladimir Sor/DZone)

Jack Shirazi

Back to newsletter 206 contents