Azul

We have got the privilege to borrow an Azul Vega 1 which is the smallest of Azul's monster machines. This evening a bunch of us Jaywayers gathered to try it out. Installing the Azul JVM was painless and all of us were up and running very quickly.

Here is screenshot from the management console showing 81 active CPUs and 23 GB free memory:

I tried some Scala actors which worked very well. By running some CPU intensive calculations I concluded that it scaled linearly up to the number of CPUs. No surprise, but very cool when you are running 80 threads at full speed! Also cool to see that Scala runs smoothly which means that neither Scala nor Azul does anything strange. Just pure bytecode.

Somebody tried to configure the Azul JVM in Eclipse and was able to run JUnit tests on Azul. We were also able to run maven without any problems.

We tried to allocate lots of memory. No problem there either, although we had to specify -Xmx10G or something. By default you only get 1.6 GB....

A colleague started tomcat, produced lots of garbage and tried garbage collection at 8 GB of heap. No pause! However, there was some synchronization problem with Log4j since all 16 CPUs had to coordinate their work.

We encountered two problems:

• xstream apparently had a dependency to Unsafe which is not supported on Azul
• the program must be headless, so no Swing

A quick rewrite later and we had generated a 64 megapixel mandelbrot calculated in parallel on 40 CPUs. The only problem was saving the PNG file which was a single threaded operation...

Jan Kronquist
Consultant at Jayway