Specification and analysis of timing constraints for embedded systems

Embedded systems consist of interacting hardware and software components that must deliver a specific functionality under constraints on relative timing of their actions. We describe operation delay and execution rate constraints, that are useful in the context of embedded systems. A delay constraint bounds the operation delay or specifies any of the thirteen possible constraints between the intervals of execution of a pair of operations. A rate constraint bounds the rate of execution of an operation and may be specified relative to the control flow in the system functionality. We present constraint propagation and analysis techniques to determine satisfaction of imposed constraints by a given system implementation. In contrast to previous purely analytical approaches on restricted models or statistical performance estimation based on runtime data, we present a static analysis in presence of conditionals and loops with the help of designer assists. The constraint analysis algorithms presented here have been implemented in a cosynthesis system, VULCAN, that allows the embedded system designer to interactively evaluate the effect of performance constraints on hardware-software implementation tradeoffs for a given functionality. We present examples to demonstrate the application and utility of the proposed techniques