Hi, all!

I have strange GHC behavior. Consider the code:

import Control.Parallel

main = print (o `par` (fromInteger e) / (fromInteger o))
where
[e,o] = map sum $ map (`filter` numbers) [even, odd]
numbers = [1..10000000]

When it compiled without threaded it has 19068 ms to run, 396 Mb total memory in use and %GC time 88.2%, the same with -threaded and +RTS -N1, but with +RTS -N2 it takes only 3806 ms to run, 3 Mb total memory in use and %GC time 8.1%. Why it so? It's a bug or I missed something?
I test it on dual-core Athlon X2 4200+ 2Gb running 64bit Gentoo system. gcc 4.2.2 and ghc 6.8.2.

--
Ruslan