Skip to main content
View by: Most Recent | Topic | Community | Webloggers   
Monthly Archives:    

Blogs by topic Performance and user kcpeppe

• Accessibility • Ajax • Blogging • Business • Community 
• Databases • Deployment • Distributed • Eclipse • Education 
• EJB • Extreme Programming • Games • GlassFish • Grid 
• GUI • IDE • Instant Messaging • J2EE • J2ME 
• J2SE • Jakarta • JavaFX • JavaOne • Jini 
• JSP • JSR • JXTA • LDAP • Linux 
• Mobility • NetBeans • Open Source • OpenSolaris • OSGi 
• P2P • Patterns • Performance • Porting • Programming 
• Research • RMI • RSS Feeds • Search • Security 
• Servlets • Struts • Swing • Testing • Tools 
• Virtual Machine • Web Applications • Web Design • Web Development Tools • Web Services and XML 


Performance

Every once in a while I run into someone that has a JVM that is running back to back collections and yet the heap is still almost full after each attempt! When they discover that their problem is related to the JVM not having enough memory they often ask the question, why didn't the JVM throw an OutOfMemoryError? After all my application is not making any forward progress and the reason is Java...
on Jan 8, 2014

Education

Just recently I was engaged to assist with an application that wasn’t behaving. The application, running in a 1.7.0_45 JVM, relied heavily on a 3rd party SAAS framework. That vendor provided my client with a list of 26 different JVM flags that should be set. When faced with this long list of flags I couldn’t resist asking why all the flags and why these flags. After all there are more than 700...
on Dec 11, 2013

Eclipse

More than a few days ago a friend pinged me complaining that recent Eclipse release was quite sluggish. Since she had taken my performance tuning seminar she knew exactly how to get and read a GC log but as we all do, she was looking for a second opinion. After looking at the log for a minute it because quite apparent that the default configuration left the IDE starved for memory. After a bit...
on Oct 21, 2012

J2EE

While I don't normally blog about the exiting world of JVM command line options, this new 7.0 option, which allows you to rotate to a new GC log file, was just so exciting... err... not so widely published that I decided to share. Of course these options only apply when you've used the -Xloggc: option. The settings are; UseGCLogFileRotation, default value: false NumberOfGCLogsFiles, default value...
on Aug 20, 2012

Testing

Today I decided it was past time to reorganize the slides in the performance testing section of the course. I added a number of new diagrams and charts to help organize the materials and then I went back and started to review some of the definitions that I was using. First up was the question; what is performance testing and how is it related to load testing.  I must confess that I derived a...
on Jan 12, 2012

Programming

I mentioned the idea to use Wordle as an execution profiler while presenting the profiling section of my performance tuning course in Paris last December. The idea was seeded by presentation that Neal Ford did a few years ago in which he used Wordle to expose the vocabulary of a Java application. Neal took a pile of source code and fed it into Wordle. The result was a word cloud that visualized...
on Jan 9, 2012

J2SE

One of the old bits of tuning advice given when Java memory management was not as tall as it it today was to set max heap to min heap. After all, we don't really want the JVM messing around with memory when it should really be getting on with things. Fast forward a few years and the adaptive memory management picture has matured considerably. So much so that setting -Xmx == to -Xms would now...
on Dec 19, 2011
Just wrapped up my last performance tuning course for this year and for the second time running, some members of my Parisian group had the opportunity to run the exercises on virtualized hardware. Granted, the underlying hardware wasn't quite top shelf but then this hardware had been un-virtualized in past offerings. And, the point is to learn how to diagnose Java performance bottlenecks and in...
on Dec 12, 2011