Hello, I am trying to use the code rels list = let o1 = (map makeCompEntry) $ head $ splitList list o2 = (map makeCompEntry) $ head $ tail $ splitList list o3 = (map makeCompEntry) $ head $ tail $ tail $ splitList list in case (head $ tail $ tail $ tail $ splitList list) of [] -> o1 `par` o2 `par` o3 `seq` o1 : o2 : o3 : [] _ -> let o4 = rels (head $ tail $ tail $ tail $ splitList list) in o1 `par` o2 `par` o3 `par` o4 `seq` o1 : o2 : o3 : o4 to apply some operation on some lists in parallel. The input list "list" is quite long (about 10^17) entries, and I split it into chunks of 1000 entries each. I am compiling with the options " -O2 --make -smp -threaded" and when running the file with "+RTS -N2 -sstderr -RTS", I see that only one worker thread is really doing anything. I am using a vanilla build of ghc-6.6.1 running on Ubuntu 7.10. I am currently wondering about what I am doing wrong. Regards, Dominik -- Dominik Luecke Phone +49-421-218-64265 Dept. of Computer Science Fax +49-421-218-9864265 University of Bremen luecke@informatik.uni-bremen.de P.O.Box 330440, D-28334 Bremen PGP-Key ID 0x2D82571B