A method of profiling transactions on an integrated circuit chip. The method comprises, for each transaction: extracting the transaction from interconnect circuitry of the integrated circuit chip; and filtering the transaction at a filtering circuit to determine which passband a parameter of the transaction lies within; sending an increment signal to a counter of a bank of counters, the counter having a counter value indicative of a number of transactions having the parameter lying within the passband; and outputting the counter values of the bank of counters.