Have posted in gcrypt-devel mailer.. thanks

Will be posting it in gcrypt-devel shortly.

Hope you've got the problem with the current naming conventions for arguments and the result by going them. We should either document the arguments properly or change the code as i have pointed out. Since the iterations argument used properly in the case PBKDF2 (type8) within the same wrapper api gcry_kdf_derive.

Here's what i got from 1.8.1 code (downloaded from gnupg).

With the current implementation when the r is set to GCRY_KDF_SCRYPT, on a 3 core system, it almost took 35 minutes to generate the hash, where as with r=41 it was around 4 minutes and 20 seconds.
when i corrected the the values, i.e. N=16384, p=1 and r=GCRY_KDF_SCRYPT, it took less than a second to generate the hash.