High-level Languages and Speed

nitsudima writes to tell us Informit's David Chisnall takes a look at the 'myth' of high-level languages versus speed and why it might not be entirely accurate. From the article: "When C was created, it was very fast because it was almost trivial to turn C code into equivalent machine code. But this was only a short-term benefit; in the 30 years since C was created, processors have changed a lot. The task of mapping C code to a modern microprocessor has gradually become increasingly difficult. Since a lot of legacy C code is still around, however, a huge amount of research effort (and money) has been applied to the problem, so we still can get good performance from the language."

Comments

Old debate

[overshoot]

Twenty years ago we were still in the midst of the "language wars" and this was a hot topic. The argument then, as now, was whether a high-level language could be compiled as efficiently as a low-level language like C [1].

Well, we ran our own tests. We took a sizable chunk of supposedly well-written time-critical code that the gang had produced in what was later to become Microsoft C [2] and rewrote the same modules in Logitech Modula-2. The upshot was that the M2 code was measurably faster, smaller, and on examination better optimized. Apparently the C compiler was handicapped by essentially having to figure out what the programmer meant with a long string of low-level expressions.

Extrapolations to today are left to the reader.

[1] I used to comment that C is not a high-level language, which would induce elevated blood pressure in C programmers. After working them up, I'd bet beer money on it -- and then trot out K&R, which contains the exact quote, "C is not a high-level language."
[2] MS originally relabled another company's C complier under license (I forget their name; they were an early object lesson.)

Re:Old debate

[shreevatsa]

For what it's worth, at The Computer Language Shootout, OCaml does pretty well. Of course, C is still faster for most things (but note that the really high factors (29 and 281) are in OCaml's favour!), but OCaml is pretty fast compared to Java or Perl. Haskell does pretty well too. Functional programming, anyone?
Of course, these benchmarks measure only speed, are just for fun, and are "flawed", but they are still interesting to play with. If you haven't seen the site before, enjoy fiddling with things to try and get your favourite language on top :)