Matthias Scheler writes:

>He is talking about smart userland code. "cp" e.g. would simply use the
>old read(2) loop in this case.

Does mmapping a file for copying instead of simply reading it really
pay off that much that it justifies complicating a silly little command
like cp, and a long thread here?  I would've thought that in a near
100% of all situations, cp was i/o (read: disk/network) bound, and the
extra kernel->userland copy was totally insignificant.

--mkb