Systems and method are disclosed for monitoring processor performance. Embodiments described relate to differentiating function performance by input parameters. In one embodiment, a method includes configuring a counter contained in a processor to count occurrences of an event in the processor and to overflow upon the count of occurrences reaching a specified value, configuring a precise event based sampling (PEBS) handler circuit to generate and store a PEBS record into a PEBS memory buffer after at least one overflow, the PEBS record containing at least one stack entry read from a stack after the at least one overflow, enabling the PEBS handler circuit to generate and store the PEBS record after the at least one overflow, generating and storing the PEBS record into the PEBS memory buffer after the at least one overflow; and storing contents of the PEBS memory buffer to a PEBS trace file in a memory.