1. A method comprising: receiving from a task layout optimizer a migration event at a plurality of compute nodes connected via a global combining network, wherein the migration event comprises a specification of a first compute node and a specification of a second compute node and a request to swap a first process that executes at the first compute node with a second process that executes at the second compute node, wherein the task layout optimizer selected the first process and the second process; performing a plurality of allreduce XOR operations at the plurality of compute nodes, wherein, in response to the migration event, the plurality of allreduce XOR operations swap the first process at the first compute node with the second process at the second compute node, wherein the performing further comprises each of the plurality of compute nodes contributes respective input to the plurality of allreduce XOR operations and receives respective output from the plurality of allreduce XOR operations, wherein the performing further comprises performing a first allreduce XOR operation on the first and the second process, wherein the first allreduce XOR operation generates a first result and storing the first result at the first compute node, wherein the performing removes the first process from the first compute node and removes the second process from the second compute node; and after the performing, executing the first process at the second compute node and executing the second process at the first compute node.