[Haskell-cafe] [Haskell] ANNOUNCE: GHC version 7.8.1

[Kazu Yamamoto (=?iso-2022-jp?B?GyRCOzNLXE9CSScbKEI=?=)]

>>   * Massive scalability improvements to the I/O manager
> 
> Just a brief note from the front lines - I recompiled a heavily threaded
> program with (a recent pre-release) of 7.8.1 and got a 10% performance
> increase over 7.6.3.  Nothing like free lunches - so thanks again for
> the great work!

Did you run you program on a multicore system? If so, did you specify
+RTS -N<x> option?

If your program uses MVar heavily, you need to re-design your program.
For more information, please read:

	http://www.yesodweb.com/blog/2014/01/new-fast-logger

--Kazu