Java Faster Than C++?

jg21 writes "The Java platform has a stigma of being a poor performer, but these new performance benchmark tests suggest otherwise. CS major Keith Lea took time out from his studies at student at Rensselaer Polytechnic Institute in upstate New York's Tech Valley to take the benchmark code for C++ and Java from Doug Bagley's now outdated (Fall 2001) "Great Computer Language Shootout" and run the tests himself. His conclusions include 'no one should ever run the client JVM when given the choice,' and 'Java is significantly faster than optimized C++ in many cases.' Very enterprising performance benchmarking work. Lea is planning next on updating the benchmarks with VC++ compiler on Windows, with JDK 1.5 beta, and might also test with Intel C++ Compiler. This is all great - the more people who know about present-day Java performance, the better.""

Comments

Languages vs Compilers

[Anonymous Coward]

Java and C++ are language. Languages aren't "faster" or "slower", but compilers for them might be. I find it somewhat underhanded to put the languages in the header when it's really comparing compilers.

Not to mention, inter-language compiler benchmark[et]ing is notoriously difficult to get 'right'. The programs tested are often stupid (doesn't do anything meaningful), or constructed by a person with more skill/bias for one language than the other.

A few points...

[mindstrm]

There seem to be some unanswered questions here..

- How equivalent were the benchmarks? Where they programmed in an optimum way for their respective compilers and libraries? I'm sure the java ones were.. what about the C++ ones? The author states he doesn't understand G++ very well.

G++ is also known to not produce the best results.

"I rant it with -O2"

My guess is many of the tests were not implemented properly in c++.

The main clue would be this... I can understand java having better than expected performance.. but there is no way I can accept that java is that much FASTER than properly done C++... it doesn't make any sense.

Expert results

[otterpop81]

Some of the C++ tests would not compile. I've never been very good at decoding GCC's error messages, so if I couldn't fix a test with a trivial modification, I didn't include it in my benchmarks.

That's Great! I can't figure out GCC's error messages, but I offer definitive proof that Java is faster than C++. Nice.

One example of why the tests are BS

[mypalmike]

From methcall.cpp:

int
main(int argc, char *argv[]) {
int n = ((argc == 2) ? atoi(argv[1]) : 1);

bool val = true;
>> Toggle *toggle = new Toggle(val);
for (int i=0; i<n; i++) {
val = toggle->activate().value();
}
cout << ((val) ? "true" : "false") << endl;
delete toggle;

val = true;
NthToggle *ntoggle = new NthToggle(val, 3);
for (int i=0; i<n; i++) {
val = ntoggle->activate().value();
}
cout << ((val) ? "true" : "false") << endl;
>> delete ntoggle;

return 0;
}

Why allocate and deallocate an object within the scope of a function? Well, in C++, there's no reason, so this is bad code. You can just declare it as a non-pointer and it lives in stack space. But guess what? You can't do that in Java: all objects are allocated on the heap.

That, and using cout instead of printf, are probably why this is slower than the "equivalent" Java.

-_-_-

Troll

[stratjakt]

This test proves that Sun's optimized Java compiler and VM are faster on Red Hat than gcc.

Gcc is designed for compatibility with a wide range of architectures, and is not optimized for a single one. He also (apparantly) used stock glibc from Red Hat. And only one "test", the method call test, showed java to be a real winner. And even then, it's server-side Java, which is meaning less when you talk about it as a day-to-day dev language (ie; creating standalone client-side apps).

Intel's (heavily optimized) C++ compiler should be a damn sight faster, and so should VC++.

This "comparison" is so limited in scope and meaning, that this writeup should be considered a troll.

Hell, read his lead-in:

"I was sick of hearing people say Java was slow, when I know it's pretty fast, so I took the benchmark code for C++ and Java from the now outdated Great Computer Language Shootout and ran the tests myself."

Ie; I set out to prove Java is teh awesome and c++ is teh suck!

If anything it proves something I've known intuitively for a long time. gcc does not produce x86 code that's as fast as it could be. That's a trade-off for it being able to compile for every friggin cpu under the sun.

I can't wait till RMS takes personal offense and goes on the attack.