[parrot/parrot] 790f34: Tune num_threads

[GitHub]

  Branch: refs/heads/threads
  Home:   https://github.com/parrot/parrot
  Commit: 790f343ef125617a17d4e45d35e9681709a4a584
      https://github.com/parrot/parrot/commit/790f343ef125617a17d4e45d35e9681709a4a584
  Author: Reini Urban <rurban at cpanel.net>
  Date:   2012-09-16 (Sun, 16 Sep 2012)

  Changed paths:
    M src/thread.c

  Log Message:
  -----------
  Tune num_threads

Via API the minimum num_threads is 2. One for sleep.

Via default Parrot_get_num_cpus() use 4 as default, if
<= 2 cpu's are found.
This leaves dual-cpu's with a bit more threads.