A technique for operating a data processing system includes detecting that a processing unit within a first group of processing units in the data processing system has a hang condition. In response to detecting that the processing unit has a hang condition, a command issue rate for the first group of processing units is reduced. One or more other groups of processing units in the data processing system are notified that the first group of processing units has reduced the command issue rate for the first group of processing units. In response to the notifying, respective command issue rates of the other groups of processing units are reduced to reduce a number of commands received by the first group of processing units from the other groups of processing units.