  The under exploitation of the available resources risks to be one of the main
problems for a computing center. The growing demand of computational power
necessarily entails more complex approaches in the management of the computing
resources, with particular attention to the batch queue system scheduler. In a
heterogeneous batch queue system, available for both serial single core
processes and parallel multi core jobs, it may happen that one or more
computational nodes composing the cluster are not fully occupied, running a
number of jobs lower than their actual capability. A typical case is
represented by more single core jobs running each one over a different multi
core server, while more parallel jobs - requiring all the available cores of a
host - are queued. A job rearrangement executed at runtime is able to free
extra resources, in order to host new processes. We present an efficient method
to improve the computing resources exploitation.
