slop

n. 1. A one-sided fudge factor , that is, an allowance for error but in only
one of two directions. For example, if you need a piece of wire 10 feet long
and have to guess when you cut it, you make very sure to cut it too long, by
a large amount if necessary, rather than too short by even a little bit,
because you can always cut off the slop but you can't paste it back on
again. When discrete quantities are involved, slop is often introduced to
avoid the possibility of being on the losing side of a fencepost error. 2.
The percentage of extra code generated by a compiler over the size of
equivalent assembler code produced by hand-hacking ; i.e., the space (or
maybe time) you lose because you didn't do it yourself. This number is often
used as a measure of the goodness of a compiler; slop below 5% is very good,
and 10% is usually acceptable. With modern compiler technology, esp. on RISC
machines, the compiler's slop may actually be negative ; that is, humans may
be unable to generate code as good. This is one of the reasons assembler
programming is no longer common.

