CPC Hardware Query Interfaces

The hardware query interfaces allow you to access process details such as counter information and events supported by the processor. The following are the hardware query interfaces:

• cpc_npic()

• cpc_caps()

• cpc_walk_events_all()

• cpc_walk_events_pic()

• cpc_walk_attrs()

uint_t cpc_npic(cpc_t *cpc);
uint_t cpc_caps(cpc_t *cpc);
void cpc_walk_events_all(cpc_t *cpc, void *arg,
          void (*action)(void *arg, const char *event));
void cpc_walk_events_pic(cpc_t *cpc, uint_t picno, void *arg, 
          void(*action)(void *arg, uint_t picno, const char *event));
void cpc_walk-attrs(cpc_t *cpc, void *arg,
          void (*action)(void *arg, const char *attr));

The cpc_npic() function returns the number of physical counters on the underlying processor.

The cpc_caps() function returns a uint_t parameter whose value is the result of the bitwise inclusive-OR operation performed on the capabilities that the underlying processor supports. There are two capabilities. The CPC_CAP_OVERFLOW_INTERRUPT capability enables the processor to generate an interrupt when a counter overflows. The CPC_CAP_OVERFLOW_PRECISE capability enables the processor to determine which counter generates an overflow interrupt.

The Oracle Solaris OS maintains a list of the events that the underlying processor supports. Different physical counters on a single chip do not have to use the same list of events. The cpc_walk_events_all() function calls the action() routine for each processor-supported event without regard to physical counter. The cpc_walk_events_pic() function calls the action() routine for each processor-supported event on a specific physical counter. Both of these functions pass the arg parameter uninterpreted from the caller to each invocation of the action() function.

The platform maintains a list of attributes that the underlying processor supports. These attributes enable access to advanced processor-specific features of the performance counters. The cpc_walk_attrs() function calls the action routine on each attribute name.