Kirk Haines wrote:

> Not unless people are running their code on multi-core processors
> where some of the cores aren't being utilized.
> 
> If superior execution time is only achieved by offloading extra work
> to an idle core, then that really isn't a gain.
>

   If that's the case, then no one would use multi-core processors at 
all.  How the threads are mapped to a processor (i.e. another core or 
not) is an OS issue.

   The issue here is that the majority of the work can be done in a 
separate thread which allows the mutator (in this case Ruby) to continue
  while the GC's thread is doing its job.

  Even if the threads are not mapped to different processors, the 
perception is that the memory manager (GC) does not stop the world to do 
its work.

KAS