Threading and the Garbage handler mess.

[Craig Black]

> There *should* be a
> benefit from collecting garbage in parallel, especially after number of
> cores raises to dozens.

Do you know something I don't?  According to my research, a separate thread 
touching everyone else's memory causes huge amounts of cache misses and page 
faults.  These far outweigh any benefit gleaned from running the GC in 
parallel.

-Craig