A system, comprising: a memory; and one or more processors (810a, 810b, 810n) coupled to the memory, wherein the memory comprises program instructions executable by the one or more processors to implement a process control component configured to: generate within the memory a stored model of multiple unit handling processes of a materials handling facility, wherein for each unit handling process the model indicates a measured throughput rate at which that unit handling process processes units, wherein at least some of the multiple unit handling processes are different types of packing stations (230a, 230b, 230n) that process units released from a random access storage buffer in order to prepare shipments of units to be shipped from the materials handling facility, wherein at least another one or more of the multiple unit handling processes is an upstream unit handling process that moves units to the random access storage buffer, wherein the upstream unit handling process moves units that will be released from the random access storage buffer to a particular one of the packing stations; based on at least one target output rate that is a goal for the output rate of a given type of pack station, evaluate the model to generate a particular target throughput rate that is a goal for the respective throughput rate of the upstream unit handling process for units moving to the given type of pack station; and based on the particular target throughput rate generated for the upstream unit handling process, generate one or more instructions to control the respective throughput rate of units being moved to the given type of pack station and processed by the upstream unit handling process. a memory; and one or more processors (810a, 810b, 810n) coupled to the memory, wherein the memory comprises program instructions executable by the one or more processors to implement a process control component configured to: generate within the memory a stored model of multiple unit handling processes of a materials handling facility, wherein for each unit handling process the model indicates a measured throughput rate at which that unit handling process processes units, wherein at least some of the multiple unit handling processes are different types of packing stations (230a, 230b, 230n) that process units released from a random access storage buffer in order to prepare shipments of units to be shipped from the materials handling facility, wherein at least another one or more of the multiple unit handling processes is an upstream unit handling process that moves units to the random access storage buffer, wherein the upstream unit handling process moves units that will be released from the random access storage buffer to a particular one of the packing stations; based on at least one target output rate that is a goal for the output rate of a given type of pack station, evaluate the model to generate a particular target throughput rate that is a goal for the respective throughput rate of the upstream unit handling process for units moving to the given type of pack station; and based on the particular target throughput rate generated for the upstream unit handling process, generate one or more instructions to control the respective throughput rate of units being moved to the given type of pack station and processed by the upstream unit handling process. generate within the memory a stored model of multiple unit handling processes of a materials handling facility, wherein for each unit handling process the model indicates a measured throughput rate at which that unit handling process processes units, wherein at least some of the multiple unit handling processes are different types of packing stations (230a, 230b, 230n) that process units released from a random access storage buffer in order to prepare shipments of units to be shipped from the materials handling facility, wherein at least another one or more of the multiple unit handling processes is an upstream unit handling process that moves units to the random access storage buffer, wherein the upstream unit handling process moves units that will be released from the random access storage buffer to a particular one of the packing stations; based on at least one target output rate that is a goal for the output rate of a given type of pack station, evaluate the model to generate a particular target throughput rate that is a goal for the respective throughput rate of the upstream unit handling process for units moving to the given type of pack station; and based on the particular target throughput rate generated for the upstream unit handling process, generate one or more instructions to control the respective throughput rate of units being moved to the given type of pack station and processed by the upstream unit handling process.