Latest entries from kirk.blog-city.com

Using Wordle as a Profiler

Kirk Pepperdine — Mon, 09 Jan 2012 12:31:00 GMT

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

Leave Comment

Building a VisualVM plugin

Kirk Pepperdine — Mon, 19 Dec 2011 12:11:00 GMT

My article on how to build a plugin for VisualVM was published today in DZone's NetBeans Zone. The code has been used to seed an open source project on java.net.

Leave Comment

Virtualization is still a performance drag

Kirk Pepperdine — Mon, 12 Dec 2011 20:24:00 GMT

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

Leave Comment

Defect Driven Design Makes a Comeback

Kirk Pepperdine — Tue, 29 Nov 2011 13:00:00 GMT

In 1996, a group that I was working with devised a development process which we called Defect Driven Design, otherwise known as D3. We were a bit disappointed by not surprised that D3 never really caught on but just recently I saw a glimmer of hope f

Leave Comment

Tool to test Java regular expression

Kirk Pepperdine — Thu, 27 Oct 2011 16:28:00 GMT

Over the last few weeks I've been working Java regular expressions into a couple of applications. After a couple of rounds with trying to sort out regular expression syntax I hacked together this handy little GUI. If anyone makes any improvements

Leave Comment

Solution to Performance Puzzler with a Stacktrace

Kirk Pepperdine — Mon, 10 Oct 2011 20:15:00 GMT

It’s after JavaONE and as promised, here is the answer to the performance puzzler with a stack trace. But first a word about JavaONE. Though the physical layout was the same as last year and as a result, JavaONE suffered from some of the same p

Leave Comment

Specification vs. Reality

Kirk Pepperdine — Tue, 04 Oct 2011 20:57:00 GMT

I'm sitting at JavaONE preparing for my session and took a minute to review the comments to my last blog posting. In the author of one comment pointed out that making a call to System.gc() is only a hint to the VM that is should run a collection.

Leave Comment

The Illusive PhantomReference

Kirk Pepperdine — Thu, 22 Sep 2011 23:48:00 GMT

PhantomReference, rarely seen in the wild, has to be the strangest of the alternate reference types. They are so strange that after sorting out how they work, I'm still left with the question, why on earth would anyone every use them.

Leave Comment

Performance Puzzler with a stack trace

Kirk Pepperdine — Wed, 07 Sep 2011 13:09:00 GMT

This performance puzzler showed up in my inbox and it's kind of interesting and so I asked the owner of this data if I might share it with you all. Here is some background. The JVM is running Tomcat with BlueDragon, a CFML engine installed. The a

Leave Comment

Proposed change to the GC efficiency calculation

Kirk Pepperdine — Mon, 11 Jul 2011 08:48:00 GMT

The industry has pretty much settled on the calculation for GC efficiency to be 1 - ( total GC pause time / application run time). It's a reasonable measure of how much CPU the parallel collectors are taking away from application (otherwise known

Leave Comment

But what about performance testing using virtualization?

Kirk Pepperdine — Fri, 08 Jul 2011 12:15:00 GMT

It's a question that I get very often. What is the effect of using virtualization in performance test environment? My answer often sounds like I'm anti-virtualization. I'm not. I think that there are plenty of great reasons to use virtual

Leave Comment

The Stolen Mobile Phone DB Works!!!

Kirk Pepperdine — Thu, 23 Jun 2011 03:11:00 GMT

stolen phone mobile database

Leave Comment

GC Log webinar

Kirk Pepperdine — Fri, 20 May 2011 12:36:00 GMT

I'm really looking forward to presenting the performance tuning course in Crete next week. This will be the second time that I've used Heinz's wonderful facilities and it marks the first time we will have 2 participants via the web. It

Leave Comment

Benchmarks Gone Wild Part II, A Hoisting We Will Go

Kirk Pepperdine — Tue, 03 May 2011 20:46:00 GMT

It’s long been taught that we should avoid performing repeated calculations in a loop. In this installment of Benchmark’s Gone Wild, I’ll examine this performance tip to see the impact it has on the performance of a simple calculati

Leave Comment

Why do I have this long GC pause?

Kirk Pepperdine — Sat, 26 Feb 2011 15:26:00 GMT

Just recently I ran into a question as why a collection took 9 seconds to complete. It's a question that comes up reasonably often and how to answer it is a topic that I give considerable attention to in my performance tuning workshop. In th

Leave Comment

Performance tuning @ JFokus

Kirk Pepperdine — Thu, 24 Feb 2011 18:02:00 GMT

The video for my performance tuning talk at JFokus is now online. Unfortunately, my last demo failed but this talk really taunted the demo gods and so.... The link is here.

Leave Comment

100% CPU with output from jstat

Kirk Pepperdine — Wed, 16 Feb 2011 08:27:00 GMT

A question about why a Java process was running at 100% recently showed up in the Java Posse forum. The author of the question had the insight to take thread dumps and use a little known but useful tool called jstat.

Leave Comment

Application Logging, why not binary?

Kirk Pepperdine — Tue, 18 Jan 2011 19:00:00 GMT

It is my experience that that evaluating data in logs files is as important as profiling when diagnosing performance bottlenecks. It's often the first bits of real information that provides insight into the nature of our woes. But it's also e

Leave Comment

UnsupportedOperationException

Kirk Pepperdine — Fri, 03 Dec 2010 14:01:00 GMT

Mostly I just get to fix code so It's not that often that I get to write code. That said, my task for the last couple of weeks has included writing a lot of code. And with it come some reminders of things I've found useful. One of the things

Leave Comment

Java Specialist Webinar

Kirk Pepperdine — Mon, 29 Nov 2010 14:23:00 GMT

Heinz has been having all kinds of fun with his Java Specialist's Webinars and so I figured I might as well elbow my way in. Now that I find myself in the final push of creating my new course, Extending VisualVM, I'm wondering if it was a goo

Leave Comment

Benchmarks Gone Wild Part 1: Watch the clock

Kirk Pepperdine — Thu, 28 Oct 2010 16:21:00 GMT

A couple of years ago I wrote this talk which I called Benchmarks Gone Wild. Yeah, I know, the title is a bit corny but I thought it would be fun to release the talk in a series of blog entries and in the process demonstrate some of the silliness tha

Leave Comment

Oracle’s Henrik Stahl responds to Doug Lea

Kirk Pepperdine — Wed, 27 Oct 2010 14:13:00 GMT

While there have been many comments about Doug Lea’s decision to leave the JCP EC including a pretty damming open letter from Doug himself, we’ve heard very little from Oracle. That is until now. Oracle’s Henrik Stahl blogged a res

Leave Comment

Larry's keynote

Kirk Pepperdine — Mon, 20 Sep 2010 12:58:00 GMT

Got to see Larry's keynote last night and it was about hardware hardware hardware. He even mentioned the acronym NUMA and then *expanded* it to non-Uniform Memory Access!!!! And we all thought Larry was all about big boats that go fast.

Leave Comment

verbose gc logging

Kirk Pepperdine — Tue, 24 Aug 2010 07:21:00 GMT

I ran into an interesting question regarding gc logging in production. The production team was hesitant to turn on gc logging because the claimed that it created a significant drag on performance. GC logging is an important aspect of monitoring appli

Leave Comment

Oracle University @ JavaONE

Kirk Pepperdine — Mon, 23 Aug 2010 13:52:00 GMT

If you look at my side bar you'll see that I'm scheduled to give a one day performance tuning seminar the day after JavaONE. I've given one day seminars at other conferences in the past.

Leave Comment