Heads-up: new parallel I/O manager merged

[Kazu Yamamoto ( 山本和彦 )]

> We should really publish a blog post about this.

- If we will take benchmark, "+RTS -Nx -qa -Aym" should be specified
  to a server. "y" should be changed according to "x", the number of
  core. I'm using "+RTS -N10 -qa -A32m" on a 12 core machine. "-qa"
  improves performance on Linux but not FreeBSD even if a "-qa" bug of
  GHC on FreeBSD is fixed.

	http://hackage.haskell.org/trac/ghc/ticket/7708

- "ab" sucks. We should use "weighttp" instead. I use as
	weighttp -n 1000000 -c 1000 -k -t 10 "http://X.Y.Z.W:8000/"
  which creates 10 native threads.

  For more information, please refer to:
	http://gwan.com/en_apachebench_httperf.html
	http://www.iij.ad.jp/company/development/tech/activities/weighttp/index.html  (in Japanese, sorry)

--Kazu