Described are techniques for controlling performance of a data storage system. A performance goal specifying a limit for an I/O class is received. A number of requests of the I/O class to be processed concurrently to achieve the performance goal so that an observed performance value for the I/O class does not exceed the performance goal is determined. If the limit is a upper bound, the observed performance value falls within a range of one or more values equal to or less than the limit, and if the limit is a minimum value, the observed performance value falls within a range of one or more values equal to or greater than the limit.