Multiple parallel slave processes and a master process are assigned to a node executing an operating system such that the operating system maintains a ready queue comprising a list of one or more processes that are ready to be executed by at least one processing core. A parallel slave process takes an action that causes the operating system to keep the parallel slave process out of the ready queue. Based on receiving an indication that the parallel slave process is to be kept out of the ready queue, the master process sets the parallel slave process to a blocking state, selects a second parallel slave process that is in a runnable state but is currently kept from being in the ready queue, and takes an action that causes the operating system to add the parallel slave process that is in the runnable state to the ready queue.