Tuesday Aug 27, 2013

My Oracle Open World and JavaOne schedule

I've got my schedule for Oracle Open World and JavaOne:

Note that on Thursday I have about 30 minutes between my two talks, so expect me to rush out of the database talk in order to get to the Java talk.

Monday Jul 08, 2013

JavaOne and Oracle Open World 2013

I'll be up at both JavaOne and Oracle Open World presenting. I have a total of three presentations:

  • Mixed-Language Development: Leveraging Native Code from Java
  • Performance Tuning Where Java Meets the Hardware
  • Developing Efficient Database Applications with C and C++

I'm excited by these opportunities - particularly working with Charlie Hunt diving into Java Performance.

Thursday Oct 18, 2012

Mixing Java and native code

This was a bit of surprise to me. The slides are available from my presentation at JavaOne on mixed language development. What I wasn't expecting was that there would also be a video of the presentation.

Wednesday Aug 29, 2012

CON6714 - Mixed-Language Development: Leveraging Native Code from Java

Here's the abstract from my JavaOne talk:

There are some situations in which it is necessary to call native code (C/C++ compiled code) from Java applications. This session describes how to do this efficiently and how to performance-tune the resulting applications.

The objectives for the session are:

  • Explain reasons for using native code in Java applications
  • Describe pitfalls of calling native code from Java
  • Discuss performance-tuning of Java apps that use native code

I'll cover how to call native code from Java, debugging native code, and then I'll dig into performance tuning the code. The talk is not going too deep on performance tuning - focusing on the JNI specific topics; I'll do a bit more about performance tuning in my OpenWorld talk later in the day.

Monday Aug 27, 2012

Monday, 1st October: Presenting at JavaOne and Oracle Open World

On Monday 1 October I will be presenting at both JavaOne and Oracle Open World. The full conference schedule is available from here. The logistics for my sessions are as follows:


  • JavaOne: 8:30am Monday 1 October. CON6714: "Mixed-Language Development: Leveraging Native Code from Java". San Francisco Hilton - Continental Ballroom 6
  • Oracle OpenWorld: 10:45am Monday 1 October. CON6382: "Maximizing Your SPARC T4 Oracle Solaris Application Performance". Marriott Marquis - Golden Gate C3

Hope to see you there!

Friday Jan 16, 2009

Out of memory in the Performance Analyzer

I've been working on an Analyzer experiment from a long running multithreaded application. Being MT I really needed to see the Timeline view to make sense of what was happening. However, when I switched to the Timeline I got a Java Out of Memory error (insufficient heap space).

Tracking this down, I used prstat to watch the Java application run and the memory footprint increase. I'd expected it to get to 4GB and die at that point, so I was rather surprised when the process was only consuming 1.1GB when the error occurred.

I looked at the commandline options for the Java process using pargs, and spotted the flag -Xmx1024m; which sets the max memory to be 1GB. Ok, found the culprit. You can use the -J option to analyzer to pass flags to the JVM. The following invocation of the analyzer sets the limit to 4GB:

$ analyzer -J-Xmx4096m test.1.er

If you need more memory than that, you'll have to go to the 64-bit JVM, and allocate an appropriate amount of memory:

$ analyzer -J-d64 -J-Xmx8192m test.1.er

Friday Mar 21, 2008

Programming for kids

A while ago I started looking for ways to get my oldest coding. My first machine was a zx-81, with 1k of memory, and most of this was used by the screen, there was a big incentive to learn assembler. I'm not out to force him into assembler programming, but...

I evaluated a number of possibilities, one was the Kid's Programming Language (or Phrogram) which can do some impressive things in few lines of code. A sample 3D space 'game' takes about 30 lines most of which look like:

	If IsKeyDown( Up ) Then
		Ship.TiltUP( moveAmount )
	End If

I also looked at squeak, but it didn't grab me as being easy to use.

An interesting alternative to real coding is c-jump, which is a programming board game. I'm not quite convinced by the syntax, or the jumping around the board.

The first thing I tried with him was Java. Which was pretty successful, but I couldn't just leave him to get on with it. There's quite a bit of syntax to have to handle. So while it was a success, it relied on me finding the time to work with him.

We then tried scratch. This has been quite successful for the following reasons:

  • It's all drag-and-drop, and the programming constructs are coloured/shaped so it's easy to put them together correctly.
  • Its all graphical, and the interface is very intuitive. You can see the object that you're programming.
  • It has an integrated graphics editor so he can draw his own sprites. Changing the look of a sprite is a step towards looking at the programming of the sprite and from there modifying the programming.
  • The biggest thing has been that he can work on this autonomously, I just have to see the end results.

The downside of scratch is that it seems a bit limited in what it can do. He really wants to do 3D games - so perhaps Phrogram is the next stop.

Any other recommendations for kids programming?

Friday May 25, 2007

Calling dtrace from Java

Recently been playing with calling dtrace scripts from Java. Its a nice api. The initial start page for learning about this is here. However, it may be more effective to look at the documentation that is included in the source. The source for some examples is also available.

About

Darryl Gove is a senior engineer in the Solaris Studio team, working on optimising applications and benchmarks for current and future processors. He is also the author of the books:
Multicore Application Programming
Solaris Application Programming
The Developer's Edge

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