From: Steve Klabnik <steve@...>
Date: 2010-11-04T03:11:23+09:00
Subject: Re: Ruby Perofrmance

--001636c5a258ccc8fb049429f724
Content-Type: text/plain; charset=ISO-8859-1

Like most things, "Ruby is slow" doesn't have a black and white answer.
You've gotta know a little bit of history. Ruby 1.8.x is called "MRI," for
"Matz's Ruby Interpreter." Now, Matz is a great language *designer*, but a
mediocre*interpreter implementor*. So, starting with Ruby 1.9, we have
"YARV," (or sometimes 'KRI') which is 'yet another ruby vm' or 'koichi's
ruby interpreter'. It's been totally re-written by people who actually care
about making Ruby as fast as possible. So the 1.8 to 1.9 gap is pretty big,
check it out:
http://shootout.alioth.debian.org/u32/benchmark.php?test=all&lang=ruby&lang2=yarv
That's
not even taking into account the other Ruby implementations, such as
Rubinius, which uses a JIT, and is already pretty damn fast, or JRuby, which
is currently the fastest Ruby implementation.

Another component of "Ruby is slow" is the whole "does it matter?" question.
I use Ruby mostly in a web context, and so my database calls tend to be the
slowest point of any given request, not Ruby itself. Basic Amdahl's law
stuff; an infinitely fast Ruby would only be marginally better at serving
pages. Even for most desktop apps, we're increasingly in a world of 2GHz
mutli-core wonder machines, and the difference in microbenchmarks just
doesn't actually matter. That's not to say that it NEVER does; my kernel
project, for example, isn't in Ruby, that'd be silly. I would never use Ruby
for scientific computing, or crunching really large numbers. My startup does
some file processing stuff; most of the site is in Rails, but that
processing is done in C. It just makes sense.

The last component is "Why is Ruby kinda slow?" Because Ruby is possibly the
most dynamic language ever created, it's a fucking *nightmare* to optimize.
All of those wonderful features that let me develop things really quickly
and have really clean, beautiful code are an absolute bitch from an
implementation standpoint. I can give you a few examples if you're curious,
I don't know how much of a compiler/language geek you are.

Anyway, I'm almost rambling. If you want to know anything else / get some
clarification, ask away. Ruby is my favorite language (followed closely by
Haskell), so anything to help spread awareness and shine some light on the
actual details!

--001636c5a258ccc8fb049429f724--