Abstract: A processor includes an execution pipeline and a retire unit coupled to an end of the execution pipeline. The processor executes instructions of a program. An apparatus for collecting performance data while the instructions are executing includes a register coupled to the retire unit of the processor. Means are provided for incrementing the register whenever an instruction is retired from the execution pipeline. In addition, the apparatus includes means for generating an interrupt to an interrupt handler whenever the register is incremented to a predetermined value.

Abstract: In a computer system, an apparatus is configured to collect performance data of a computer system including a plurality of processors for concurrently executing instructions of a program. A plurality of performance counters are coupled to each processor. The performance counters store performance data generated by each processor while executing the instructions. An interrupt handler executes on each processors, the interrupt handler samples the performance data of the processor in response to interrupts. A first memory includes a hash table associated with each interrupt handler, the hash table stores the performance data sampled by the interrupt handler executing on the processor. A second memory includes an overflow buffer, the overflow buffer stores the performance data while portions of the hash tables are active or full. A third memory includes a user buffer, and means are provided for periodically flushing the performance data from the hash tables and the overflow to the user buffer.