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CPython vs. Jython/JPython

Greg Jorgensen gregj at pobox.com
Sat Nov 4 15:16:45 EST 2000 
"Ingo Adler" <ingo.adler at synacon.ch> wrote in message
news:39FF4663.A7B5E81E at synacon.ch...
> Bill de hÓra wrote:
>
> > Raw C written by a good programmer is typically more efficient in space
...
>
> There are benchmarks that show the opposite.

Benchmarks may show a lot of things, but they can't show that Java can be
MORE efficient than ANSI C, controlling for other variables. That would be
equivalent to asserting that Michael Jordan with a 50 pound weight on his
back can play better than Michael Jordan without the weight. You don't need
benchmarks to understand that the weighted Jordan can't possibly be FASTER
or take up LESS space than the unweighted Jordan. It would be easy to
demonstrate that even the weighted Michael Jordan could beat me in a game,
though. That's what the benchmarks you are referring to show.

There is no way that a Java program can be faster than the equivalent C
program, on the same computer, if the best practices and idioms of each
language are followed. Of course a skilled programmer using Java (or Visual
Basic, for that matter) can write more efficient code than a bad C
programmer, but that's comparing programmers, not languages.

C is often described as a portable macro assembler. Well-written C programs
can be almost as efficient as hand-written assembly, but never MORE
efficient (again, think of ideal C and assembly programmers, not the average
programmer who barely knows how to read assembly). By the same token, Java
compilers, JVMs, and libraries are usually implemented in C, so Java is in a
sense a portable "macro" C. The runtime support required to interpret (or
compile "just in time") and execute a Java programmer can never be MORE
efficient than not having that runtime support at all: the JVM and bytecode
interpreter/compiler always uses some amount of memory and CPU cycles that
the C program doesn't have to give up.

By the same argument Java can't be MORE portable than ANSI C. The current
state of JVMs demonstrates the difficulty of achieving "write once, run
everywhere." Perhaps this will improve over time, but as long as Java is
proprietary it is going to be a vendor battlefield.

Java is a higher-level language than C, and the language protects the
programmer from the headaches of C (memory management, pointers, abuse of
type conversions). Programmer time and maintenance effort should be given at
least as much weight--and probably more weight--than runtime efficiency.

--
Greg Jorgensen
Deschooling Society
Portland, Oregon, USA
gregj at pobox.com
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