A method and system for the management of tracing data of interest in a data processing system comprises identifying the location and length of one or more such units of interest as each unit is stored in main memory during execution of the program and recording a logical assignment of each unit of interest to a slot in a wrap around trace buffer. Copying of the units of interest to the trace buffer is deferred unless one or more predefined events occur. Such events may include an attempt to overwrite the data which has been logically assigned or a request for information stored in the trace buffer. The recorded assignments are discarded whenever it is calculated that the capacity of the trace buffer would be exceeded resulting in the corresponding units never needing to be copied to the trace buffer.