Jrg W Mittag wrote:
>
> In other words, if you want to measure Ruby 1.9 vs. Ruby 1.8, measure
> Ruby 1.9 vs. Ruby 1.8 and not Ruby 1.9 and YARV vs. Ruby 1.8 and MRI,
> because that way you will never know whether the performance
> difference came from Ruby 1.9, YARV or a combination of the two.

The confusion is understandable.

Historically, on the Matz lineage of interpreters, ruby 1.9 (formerly
ruby 2.0) had long been associated with several key feature bullet
points, particularly:

  * new VM for increased speed
  * multinationalization support

I joined ruby-talk in 2001, and it was being discussed even then.
Originally the new VM was to be called Rite instead of YARV, and it
was expected to debut in ruby 2.0 instead of 1.9:

http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-talk/23267


These days, when we look at other ruby interpreters, such as JRuby,
it's easy to see that 1.8 vs. 1.9 language semantics are orthogonal
to the VM.  So, indeed, on JRuby (for example), one can benchmark
1.8 semantics vs. 1.9 semantics without changing the VM.

But in the Matz lineage, 1.8 implies MRI, and 1.9 implies YARV.

Further, the new VM was always understood to be the primary *reason*
to expect speed improvements from 1.8 -> 1.9 in the Matz lineage.


Regards,

Bill