Event monitoring in a system-on-a-chip

This paper presents a novel approach for monitoring disjunct, concurrent operations in heavily queued systems. A non-obtrusive activity monitor is used as an on-chip tracing unit. For each pending operation the monitor uses the hardware implementation of an event triggered operation graph to trace the path of the operation through the system. Other than conventional tracing units that collect and record information from one or more functional units for later analysis, the presented solution directly records the path of the operation through the system, enabling an immediate analysis of operation inconsistencies. For each followed path a unique signature is generated that significantly reduces the amount of trace data to be stored. The trace information is stored together with a time stamp for debugging and measuring of queuing effects and timing behavior in the system. The presented method has been successfully applied to an IO-Adapter-chip in IBM's S/390 G5 and G6 Systems.