Patent ID: 8176366

Claim:
A data processing apparatus having one or more trace data sources, said trace data sources operating to generate respective streams of trace data, at least one of said trace data sources comprising: a trace data generator responsive to activity in monitored circuitry to generate trace data representing said activity; a synchronization marker generator coupled to said trace data generator, said synchronization marker generator operating to generate a synchronization marker and insert said synchronization marker into said trace data stream, said synchronization marker identifying a synchronization position in said trace data stream; and a controller coupled to said synchronization marker generator, said controller operating to initiate said synchronization marker generator to generate and insert said synchronization marker into said trace data stream; wherein said controller controls initiation in dependence on behavior of said data processing apparatus downstream of said trace data generator with respect to trace data flow, wherein: said at least one trace data source is arranged to receive a plurality of synchronization requests for requesting initiation of said synchronization marker generator; said at least one trace data source comprises arbitration logic for arbitrating between said plurality of synchronization requests and for selecting one of said plurality of synchronization requests to be serviced; and said controller is responsive to selection of said synchronization request to be serviced to initiate said synchronization marker generator.