Hardware performance counter
From Wikipedia, the free encyclopedia
In computers, hardware performance counters, or hardware counters are a set of special-purpose registers built in modern microprocessors to store the counts of hardware-related activities within computer systems. Advanced users often rely on those counters to conduct low-level Performance analysis or tuning.
The number of available hardware counters in a processor is often quite limited. The following table shows some examples:
| Processor | available HW counters |
|---|---|
| UltraSparc II | 2 |
| Pentium III | 2 |
| AMD Athlon | 4 |
| IA-64 | 4 |
| POWER4 | 8 |
| Pentium 4 | 18 |
