Embedded Java - JavaTech: An Introduction to Scientific and Technical Computing with Java - page 680

24.11 Java processor performance
Java processors, whether virtual or in hardware, vary greatly in their performance
capabilities. Many embedded applications, such as controlling an appliance, do
not need tremendous speed. On the other hand, some applications, such as creating
detailed animations for a PDA screen, do require high performance.
There is no universally accepted set of benchmarks for measuring Java pro-
cessing performance (though at least one organization is trying to develop them
[33]). One popular measure of Java processing speed, however, is the Caffeine-
Mark developed by Pendragon Software [34] in the mid-1990s. It consists of
a suite of tests such as a prime number search, recursive method invocations,
drawing images, and so forth. Another measure is the VolanoMark, developed
by Jeff Neffenger, which emphasizes server performance [35].
Benchmarks are never perfect, and you can usually find some bias that favors
one system over another. In general, it is best to focus on the particular platform
and the features desired and compare only the systems that could fulfill those
requirements. There is no point in comparing, say, the Javelin Stamp with a JVM
running on a modern desktop machine. The more advanced chips can perform at
higher speeds and offer floating-point, but many do not offer the performance of
even a modest desktop-level machine. For example, in a series of tests involving
tasks such as sorting and pattern recognition, a 1.6-GHz Pentium was roughly
100 times faster than an aJile evaluation board with the aJ-100 chip [36].
More of an apples versus apples comparison is given in Table 24.1. It shows
a comparison of speeds for several types of operations for the SNAP board from
Imsys Technologies, which uses a hardware Java processor, and a standard TINI TM
board that uses a JVM running in a conventional microcontroller. For these tests,
the hardware approach provides one to two orders of magnitude faster speed [15].

24.12 Web Course materials
In addition to more details about the chips, boards, and programs discussed
here, the Web Course Chapter 24 offers more examples and demonstrations of
embedded Java. Code listings, diagrams, and other resources are included. As
new Java hardware is introduced, these will be added to the resources section.

References

[1] Java Card at Sun Microsystems, http://java.sun.com/products/javacard/ .
[2] Kim Topley, J2ME in a Nutshell , 2002, O'Reilly.
[3] KVM Porting Guide, CLDC, Version 1.1, Java TM 2 Platform, Micro Edition , Sun

Microsystems, Inc., March 2003.
[4] Tim Lindholm and Frank Yellin, The Java TM Virtual Machine Specification, 2nd Edn,
Sun Microsystems, Inc. 1999, http://java.sun.com/docs/books/vmspec/ .