Locality of reference and the use of Sojourn time variance for measuring queue unfairness extended abstract

The variance of customer sojourn time (or waiting time) is used, either explicitly or implicitly, as an indication of fairness for as long as queueing theory exists. In this work we demonstrate that this quantity has a disadvantage as a fairness measure, since it is not local to the busy period in which it is measured. It therefore may account for customer discrepancies which are not relevant to fairness of scheduling. We show that RAQFM, a recently proposed job fairness measure, does possess such a locality property. We further show that within a large class of fairness measures RAQFM is unique in possessing this property.