illumos: manual page: cpc

CPC_NPIC(3CPC) CPU Performance Counters Library Functions CPC_NPIC(3CPC)

NAME

cpc_npic, cpc_caps, cpc_cciname, cpc_cpuref, cpc_walk_events_all,
cpc_walk_generic_events_all, cpc_walk_events_pic,
cpc_walk_generic_events_pic, cpc_walk_attrs - determine CPU performance
counter configuration

SYNOPSIS

cc [ flag... ] file... -lcpc [ library... ]
#include <libcpc.h>

uint_t cpc_npic(cpc_t *cpc);

uint_t cpc_caps(cpc_t *cpc);

const char *cpc_cciname(cpc_t *cpc);

const char *cpc_cpuref(cpc_t *cpc);

void cpc_walk_events_all(cpc_t *cpc, void *arg,
void (*action)(void *arg, const char *event));

void cpc_walk_generic_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_generic_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));

DESCRIPTION

The cpc_cciname() function returns a printable description of the
processor performance counter interfaces, for example, the string
UltraSPARC III+ & IV. This name should not be assumed to be the same as
the name the manufacturer might otherwise ascribe to the processor. It
simply names the performance counter interfaces as understood by the
system, and thus names the set of performance counter events that can be
described by that interface.

The cpc_cpuref() function returns a string that describes a reference
work that should be consulted to (allow a human to) understand the
semantics of the performance counter events that are known to the system.
The string returned might be substantially longer than 80 characters.
Callers printing to a terminal might want to insert line breaks as
appropriate.

The cpc_npic() function returns the number of performance counters
accessible on the processor.

The cpc_caps() function returns a bitmap containing the bitwise
inclusive-OR of zero or more flags that describe the capabilities of the
processor. If CPC_CAP_OVERFLOW_INTERRUPT is present, the processor can
generate an interrupt when a hardware performance counter overflows. If
CPC_CAP_OVERFLOW_PRECISE is present, the processor can determine
precisely which counter overflowed, thereby affecting the behavior of the
overflow notification mechanism described in cpc_bind_curlwp(3CPC).

The system maintains a list of performance counter events supported by
the underlying processor. Some processors are able to count all events on
all hardware counters, while other processors restrict certain events to
be counted only on specific hardware counters. The system also maintains
a list of processor-specific attributes that can be used for advanced
configuration of the performance counter hardware. These functions allow
applications to determine what events and attributes are supported by the
underlying processor. The reference work pointed to by cpc_cpuref()
should be consulted to understand the reasons for and use of the
attributes.

The cpc_walk_events_all() function calls the action function on each
element of a global event list. The action function is called with each
event supported by the processor, regardless of which counter is capable
of counting it. The action function is called only once for each event,
even if that event can be counted on more than one counter.

The cpc_walk_events_pic() function calls the action function with each
event supported by the counter indicated by the picno argument, where
picno ranges from 0 to the value returned by cpc_npic().

The system maintains a list of platform independent performance counter
events known as generic events (see generic_events(3CPC)).

The cpc_walk_generic_events_all() function calls the action function on
each generic event available on the processor. The action function is
called for each generic event, regardless of which counter is capable of
counting it. The action function is called only once for each event,
even if that event can be counted on more than one counter.

The cpc_walk_generic_events_pic() function calls the action function with
each generic event supported by the counter indicated by the picno
argument, where picno ranges from 0 to the value returned by cpc_npic().

The system maintains a list of attributes that can be used to enable
advanced features of the performance counters on the underlying
processor. The cpc_walk_attrs() function calls the action function for
each supported attribute name. See the reference material as returned by
cpc_cpuref(3CPC) for the semantics use of attributes.

RETURN VALUES

The cpc_cciname() function always returns a printable description of the
processor performance counter interfaces.

The cpc_cpuref() function always returns a string that describes a
reference work.

The cpc_npic() function always returns the number of performance counters
accessible on the processor.

The cpc_caps() function always returns a bitmap containing the bitwise
inclusive-OR of zero or more flags that describe the capabilities of the
processor.

If the user-defined function specified by action is not called, the
cpc_walk_events_all(), cpc_walk_events_pic(), cpc_walk_attrs(),
cpc_walk_generic_events_pic(), and cpc_walk_generic_events_pic()
functions set errno to indicate the error.

ERRORS

The cpc_walk_events_all(), cpc_walk_events_pic(), cpc_walk_attrs(),
cpc_walk_generic_events_pic(), and cpc_walk_generic_events_pic()
functions will fail if:

ENOMEM
There is not enough memory available.