Hi there, I was not able to parallelize the below code by "parListChunk" strategy. Actually, code works fine without ant mistake in the result but no improvement in the performance handled. Threadscope demonstrates that parallelization happens after the sequential run of the program which is meaningless. In short, parListChunk is not working as intended. As far as I know, it should divide an arbitrarily given list into its chunks and then apply the given function to each sub-list (chunk) in parallel with reducing the evaluation of each element of each chunk into head normal form, if you use "rdeepseq" as the input strategy. In the below code, I want to divide the given list into 2000 chunks and then apply "ersa" function to each chunk in parallel with evaluating each element into its head normal form in serial internally. However, as I wrote, it first runs in serial after than the parallel scenario I admire to happen at the beginning happens. How can I solve this problem? Thanks in advance, Burak. ersa :: RSAPublicKey -> [Integer] -> [Integer] ersa (PUB n e) (x:xs) = ersa (PUB n e) (xs) ++ [expm n x e] ersa (PUB n e) [] = [] splitToEnc :: RSAPublicKey -> [Integer] -> [Integer] splitToEnc (PUB n e) [] = [] splitToEnc (PUB n e) (x:xs) = (ersa (PUB n e) (x:xs)) `using` parListChunk 2000 rdeepseq