Thomas Glanzmann wrote:

For tar I have no idea why it should slow down the operation, but maybe
you can enlighten us.

Directory hashing slows down operations that do linear sweeps through 
the filesystem reading every single file, simply because without 
dir_index, there is likely to be a correlation between inode order and 
directory order, whereas with dir_index, readdir() returns entries in 
hash order.

	-hpa