1. A system for executing a process that includes a plurality of sub-operations, the system comprising: a shared memory; a cluster-to-cluster communication channel; a plurality of processor clusters that are together capable of executing the process, wherein each respective cluster includes: a group of processors of a specific class different from classes of processors of other processor clusters; a database configured to store, for each respective sub-operation, of the plurality of sub-operations, that the respective cluster is assigned to execute, an identification of classes of processors that are capable of executing the respective sub-operation, an identification of at least one downstream sub-operation comprising another sub-operation, of the plurality of sub-operations, that is configured to input data that is output by the respective sub-operation, an identification of whether the respective sub-operation is ready to be performed, based on completion of all sub-operations to which the respective sub-operation is a downstream sub-operation, and an expiry time threshold; a processor assigner configured to select a ready first sub-operation from the ready sub-operations, identify a processor, from among the processors of the respective cluster, that is of a class that is identified in the respective cluster's database as capable of executing the selected ready first sub-operation, assign the selected ready first sub-operation to the identified processor to execute the selected ready first sub-operation, and store, in the shared memory, results of execution of the first sub-operation; a downstream cluster processor assigner configured to, identify a sub-operation, of the plurality of sub-operations, that is a downstream sub-operation of the executed first sub-operation, identify a cluster, of the plurality of clusters, that includes a processor that is of a class that is capable of executing the downstream sub-operation and that is different from the cluster that executed the first sub-operation, and assign the downstream sub-operation through the cluster-to-cluster communication channel to the identified cluster, for the identified cluster to execute the downstream sub-operation accessing the results of first sub-operation from the shared memory; and a processor re-assigner configured to, in response to a ready sub-operation having remained unexecuted in the respective cluster beyond the expiry time threshold, re-assign the ready sub-operation for execution to another processor cluster that includes a processor that is of a class that is capable of executing the ready sub-operation.