[Haskell-beginners] sequential code linked against nonthreaded lib vs. concurrent/parallel code linked against threaded runtime lib, both on one core

[Hong Yang]

Hi,

I am reading "Choosing the Right Runtime" section of the "Real World
Haskell" book, and having a question.

There are typically four cases as follows:
   case # code linking RTS -N  1 sequential non-threaded 1  2
concurrent/parallel non-threaded 1  3 concurrent/parallel threaded 1  4
concurrent/parallel threaded > 1
Case #4 may or may not be faster than #3. But #3 is definitely slower than
#1 and #2, due to overhead from threaded runtime lib.

Now my question is, how does #2 compare with #1? (#2 must make sense,
otherwise it would not be an option, and the book authors would not have
specifically talked about it in one section.) Are the authors implying #2
may be potentially much faster than #1? If there were no such potential,
one would just write sequential codes without attempting
concurrent/parallel style, under the circumstances where his job is limited
to one core.

Thanks,

Hong
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.haskell.org/pipermail/beginners/attachments/20130426/2c899e1c/attachment.htm>