Assuming that the total amount of computation in a parallel code
fragment (or, for the purposes of this paper, a parallel loop nest)
is
which is distributed amongst processors in such a way that each processor
, , is assigned an amount of computation equal to
(clearly,
), then we say that this distribution
exhibits a load imbalance, , equal to
To assess the impact of load imbalance on performance, we introduce
relative load imbalance, , defined as