This paper proposes a new strategy to integrate shared resources and precedence constraints among real-time tasks, assuming
no precise information on critical sections and computation times is available. The concept of bandwidth inheritance
is combined with a capacity sharing and stealing mechanism to efficiently exchange bandwidth among tasks to minimise the
degree of deviation from the ideal system’s behaviour caused by inter-application blocking.
The proposed Capacity Exchange Protocol (CXP) is simpler than other proposed solutions for sharing resources in open
real-time systems since it does not attempt to return the inherited capacity in the same exact amount to blocked servers. This
loss of optimality is worth the reduced complexity as the protocol’s behaviour nevertheless tends to be fair and outperforms
the previous solutions in highly dynamic scenarios as demonstrated by extensive simulations.
A formal analysis of CXP is presented and the conditions under which it is possible to guarantee hard real-time tasks are
discussed
