Performance measurements

Performance measurements
© 2003 Jean-Marc Vanel

Last update:

Introduction

I wanted to have a clear idea of Java performance compared to C++. So I did a simple program with 1 billion of multiplications. Later I added tests for other ways of running a Java class. Still later I tested Eiffel, probably the best all-purposes language.

There are other execution environments possible. At the kaffe.org site, there are many projects aiming to run Java in unusual ways. While I was here, I tried kaffe 1.1.3; installation didn't succeed on Fedora Linux, so I posted a message on their list, and had a kind reply but alas it is not currently compatible with Fedora; I should retry with latest gcc and glibc.

The test machine is a 500 MHz PC with Fedora RedHat Linux; it is a network gateway so we don't get 100% of the CPU. So the figures are just an order of magnitude in a real-world situation. I could have taken in account the CPU% given by the time command.

MesurePerf.cpp - typescript-cpp.txt
MesurePerf.java - typescript-java.txt
Eiffel class

Results

Elapsed times in milliseconds.

Language	Platform and/or compiler	non optimized	optimized
Java	Sun JVM (1.4.2 or 1.5.0 beta)		38744
Java	gcj	67645	22810
Java	gij, GNU Java bytecode interpreter	743068
Java	Jikes RVM , an open source JVM from IBM	126923	15084
C++	gcc	18610	3690
Eiffel	ISE EIFFELSTUDIO		3570
Eiffel	SmallEiffel	18772	10125

Comments

Java + JVM Sun is 10 times slower than C++ ! I thought the famous Just-In-Time compiler would do better;
"conceptually" optimized gcj should be as quick as g++ , we can expect large progresses
nevertheless it pays to use gcj when possible (almost a factor 2)
Jikes RVM is an interesting project that is used by numerous other projects that extend Java platform in various ways; it does better than native executable compiled from Java by gcj !
Sun has improved, at least on Linux, the loading time; a minimal console application now runs in 0.6 second, compared to 3.5 seconds for Jikes RVM, 0.21 s for gcj (and 0.03 second with Perl !)
Eiffel is a nice object-oriented language that allready existed in 1985 and is still superior to Java in clean design; there is also an IDE called EIFFELSTUDIO; however it is not free like Java; you have to pay for commercial use (otherwise you get an executable printing "This program has been produced with a demo or non-commercial version of ISE EiffelStudio, ...". This language, from a pure technical point of vue, has all the advantages: as quick as C++, genericity, design by contract, multiple inheritance, clean properties (no-argument function call is identical to property accessor). While removing many of the hassles of Java and C++, you can call Java from Eiffel, and even compile Eiffel to Java bytecode. There are 3 pages of Eiffel projects in sf.net . There is also SmallEiffel The GNU Eiffel Compiler, the one which has the Java bytecode compiler. And with alma (also from french origin !) there is a way to translate Java to Eiffel; of course it will translate the core language, not the calls to Java foundation classes.