Over last 12 years, Java has become almost de facto in application development paradigm. Initial days were complaining about the performance of Java programs. However there is no doubt that enormous efforts that have been put in optimization of Java compiler and JVM implementations, have given handsome returns. But we know, rather we need to know, that there is an upper limit to this optimization for performance, being implemented as a software. Despite Java’s wide acceptance, Java Virtual Machines are limited to be software deployments. There is an emerging need, to have Java Virtual Machine in hardware.
Fortunately the space is not an entirely unexplored territory. There were several efforts to implement Java processors and including PicoJava, one of them from Sun Microsystems. It seems a very promising concept and it should become more and more relevant in days to come. Imagine a system with many cores, for example ‘SUN UltraSPARC T2‘ that has 8 cores per CPU. Now all these cores are identical and a server with 8-way configuration would have 64 cores. This kinds of systems leave a lot of room for something called as ‘Domain-specific Processors’, hence it makes lot of sense to have four dedicated Java processors part of the system. One of such example is presented by IBM for its System Z Application Assist Processor(zAAP). Primary benefit of having such processors would be their specialization. Such processors can be optimized to a larger extent, they can be upgraded frequently and would be cheaper. Apart from that, these processors leave the main general purpose processors free to do their tasks. Thus a Java Processor can be a co-processor to your main processor. Remember the known examples such as ‘Intel 387’ or today’s Graphics Processing Units (GPUs). Checkout some benchmarks for IBM’s zAAP.
Another very interesting initiative is from Bea Systems, that talks about JVM Hypervisor. This can, meanwhile, provide some breathing space. The idea was, I guess, first presented by Joakim Dahlstedt (CTO of Bea) at JavaOne 2006. One can find PDF of the presentation here – “Bare Metal”—Speeding Up Java™ Technology in a Virtualized Environment.