4.8. Probes to monitor performance
The perfmon family of probe points is used to access the performance monitoring hardware available in modern processors. These probe points require perfmon2 support in the kernel to access the hardware.
Performance monitor hardware points have a
perfmon prefix. The suffix names the event being counted, for example counter(event). The event names are specific to the processor implementation, except for generic cycle and instructions events, which are available on all processors. The probe perfmon.counter(event) starts a counter on the processor which counts the number of events that occur on that processor. For more details about the performance monitoring events available on a specific processor, see the help text returned by typing the perfmon2 command pfmon -l.
4.8.1. $counter
$counter is a handle used in the body of a probe for operations involving the counter associated with the probe.
4.8.2. read_counter
read_counter is a function passed to the handle for a perfmon probe. It returns the current count for the event.
