1. A method comprising: allocating a quantity of processors for processing a job in a high-performance computing environment to provide an initial allocation; and modifying the initial allocation during a run time of the job by performing one or more of: increasing the allocated quantity of processors in response to the job being extended in size by allocating one or more free processors from a pool of free processors which are configured to meet an increased computing demand for the job; or decreasing the allocated quantity of processors in response to the job being decreased in size by reallocating one or more processors from the allocated quantity of processors to the pool of free processors.