In many parallel processing systems, particularly real-time systems, it is desirable for jobs to finish as close to a target time as possible. This work examines a method of controlling the variance of job completion times by dynamically allocating resources to jobs that are behind schedule and taking resources from jobs that are ahead of schedule. Emphasis is placed on where variance enters the systemand how well it can be controlled. Controlling the variance also helps meet deadlines because the number of standard deviations between the target and the deadline determines the probability of missing the deadline.