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

int cpc_strtoevent(int cpuver, const char *spec, cpc_event_t *event);

char *cpc_eventtostr(cpc_event_t *event);

The cpc_strtoevent() function translates an event specification to the appropriate collection of control bits in a cpc_event_t structure pointed to by the event argument. The event specification is a getsubopt(3C)-style string that describes the event and any attributes that the processor can apply to the event or events. If successful, the funciton returns 0, the ce_cpuver field and the ISA-dependent control registers of event are initialized appropriately, and the rest of the cpc_event_t structure is initialized to 0.

The cpc_eventtostr() function takes an event and constructs a compact canonical string representation for that event.

Upon successful completion, cpc_strtoevent() returns 0. If the string cannot be decoded, a non-zero value is returned and a message is printed using the library's error-reporting mechanism (see cpc_seterrfn(3CPC)).

Upon successful completion, cpc_eventtostr() returns a pointer to a string. The string returned must be freed by the caller using free(3C). If cpc_eventtostr() fails, a null pointer is returned.

The event selection syntax used is processor architecture-dependent. The supported processor families allow variations on how events are counted as well as what events can be counted. This information is available in compact form from the cpc_getusage() function (see cpc_getcpuver(3CPC)), but is explained in further detail below.

On UltraSPARC processors, the syntax for setting options is as follows:

pic0=<eventspec>,pic1=<eventspec> [,sys] [,nouser]

This syntax, which reflects the simplicity of the options available using the %pcr register, forces both counter events to be selected. By default only user events are counted; however, the sys keyword allows system (kernel) events to be counted as well. User event counting can be disabled by specifying the nouser keyword.

The keywords pic0 and pic1 may be omitted; they can be used to resolve ambiguities if they exist.

On Pentium processors, the syntax for setting counter options is as follows:

pic0=<eventspec>,pic1=<eventspec> [,sys[[0|1]]] [,nouser[[0|1]]]
[,noedge[[0|1]]] [,pc[[0|1]]]

The syntax and semantics are the same as UltraSPARC, except that is possible to specify whether a particular counter counts user or system events. If unspecified, the specification is presumed to apply to both counters.

There are some additional keywords. The noedge keyword specifies that the counter should count clocks (duration) instead of events. The pc keyword allows the external pin control pins to be set high (defaults to low). When the pin control register is set high, the external pin will be asserted when the associated register overflows. When the pin control register is set low, the external pin will be asserted when the counter has been incremented. The electrical effect of driving the pin is dependent uptoon how the motherboard manufacturer has chosen to connect it, if it is connected at all.

For Pentium II processors, the syntax is substantially more complex, reflecting the complex configuration options available:

pic0=<eventspec>,pic1=<eventspec> [,sys[[0|1]]]
[,nouser[[0|1]]] [,noedge[[0|1]]] [,pc[[0|1]]] [,inv[[0|1]]] [,int[[0|1]]]
[,cmask[0|1]=<maskspec>] [,umask[0|1]=<maskspec>]

This syntax is a straightforward extension of the earlier syntax. The additional inv, int, cmask0, cmask1, umask0, and umask1 keywords allow extended counting semantics. The mask specification is a number between 0 and 255, expressed in hexadecimal, octal or decimal notation.

Example 1 SPARC Example.

cpc_event_t event;
char *setting = "pic0=EC_ref,pic1=EC_hit"; /* UltraSPARC-specific */

if (cpc_strtoevent(cpuver, setting, &event) != 0)
 /* can't measure 'setting' on this processor */
else
 setting = cpc_eventtostr(&event);

See attributes(5) for descriptions of the following attributes:

cpc(3CPC), cpc_getcpuver(3CPC), cpc_set_add_request(3CPC), cpc_seterrfn(3CPC), free(3C), getsubopt(3C), libcpc(3LIB), attributes(5)

The cpc_strtoevent() and cpc_eventtostr() functions exist for binary compatibility only. Source containing these functions will not compile. These functions are obsolete and might be removed in a future release. Applications should use cpc_set_add_request(3CPC) instead.

These functions are provided as a convenience only. As new processors are usually released asynchronously with software, the library allows the pic0 and pic1 keywords to interpret numeric values specified directly in hexadecimal, octal, or decimal.