man pages section 3: Extended Library Functions, Volume 1

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Updated: July 2014
 
 

cpc_walk_smpl_recitems(3CPC)

Name

cpc_npic, cpc_smpl_npic, cpc_caps, cpc_cciname, cpc_smpl_iname, cpc_cpuref, cpc_walk_events_all, cpc_walk_events_all_common, cpc_walk_generic_events_all, cpc_walk_events_pic, cpc_walk_events_pic_common, cpc_walk_generic_events_pic, cpc_walk_attrs, cpc_walk_attrs_common, cpc_walk_smpl_recitems, cpc_get_smpl_max_rec_count, cpc_walk_smpl_recitems_req - determine CPU performance counter configuration

Synopsis

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

uint_t cpc_npic(cpc_t *
cpc);
uint_t 
cpc_smpl_npic(cpc_t *cpc);
uint_t cpc_caps(
cpc_t *cpc);
const char *cpc_cciname(
cpc_t *cpc);
const char *cpc_smpl_iname(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_events_all_common(cpc_t *
cpc, void *
arg, 
		int target, 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_events_pic_common(cpc_t *
cpc, uint_t 
picno, void *arg, 
		int target, 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));
void cpc_walk_attrs_common(cpc_t *
cpc, void *arg, 
		int target, void (*
action) (void *arg, 
const char *attr));
void cpc_walk_smpl_recitems(cpc_t *
cpc, void *
arg, 
		void (*action)(
void *arg, const char *
name, int record_item_index));
void cpc_walk_smpl_recitems_req
(cpc_t *cpc, 
cpc_set_t *set, int 
request_index, void *arg, 
		void (*action)(void *
arg, cpc_set_t *
set, int request_index, 
		const char *name, int
 record_item_index));
int cpc_get_smpl_max_rec_count(cpc_t *
cpc, uint_t 
max_rec_count);

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_smpl_iname() function returns the hardware sampling implementation name available on the processor. Currently, only PEBS for Intel Precise Events Based Sampling is supported as the hardware sampling implementation name.

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 for CPC accessible on the processor. On the processor that shares the performance counters between CPC and SMPL, the reported number is still the one counting the performance counters that could be used for CPC. Therefore, the number may contain the one for the performance counters that could be also used for SMPL.

The cpc_smpl_npic() function returns the number of performance counters for SMPL accessible on the processor. On the processor that shares the performance counters between CPC and SMPL, the reported number is still the one counting the performance counters that could be used for SMPL. Therefore, the number may contain the one for the performance counters that could be also used for CPC. If the specified cpc has not been successfully opened for SMPL, cpc_smpl_npic() sets EINVAL to errno and returns 0.

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). If CPC_CAP_SMPL is present, the hardware sampling is available on the processor. If CPC_CAP_OVERFLOW_SMPL is present, the hardware sampling available on the processor supports the overflow. If cpc_open() with CPC_VER_CURRENT successfully returned a CPC handle, it is still unknown if the CPC handle can work not only for CPC but also SMPL. To determine if the CPC handle can work for SMPL, cpc_caps () needs to be used to check CPC_CAP_SMPL is present in the returned capabilities.

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 that supports CPC. 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_all_common() function calls the action function on each element of a global event list that supports the performance monitoring type specified by target . The supported performance monitoring type is either CPC_CPC for specifying the CPC performance events or CPC_SMPL for specifying the SMPL performance events. The cpc_walk_events_all_common() function with CPC_CPC as target is equivalent to cpc_walk_events_all().

The Supported macros for target are:

CPC_CPC

for specifying CPC performance monitoring type

CPC_SMPL

for specifying SMPL performance monitoring type

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

The cpc_walk_events_pic_common () function calls the action function with each event associated with the performance monitoring type specified by target and supported by the counter indicated by picno argument, where picno ranges [0, value returned by cpc_npic()) when target is CPC_CPC, or [0, value returned by cpc_smpl_npic()) when target is CPC_SMPL.

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 attribute name supported for CPC.

The cpc_walk_attrs_common() function calls the action function for each attribute name supported for the performance monitoring type specified by target. The function cpc_walk_attrs_common () with CPC_CPC as target is equivalent to cpc_walk_attrs().

See the reference material as returned by cpc_cpuref(3CPC) for the semantics use of attributes.

The result of the SMPL request is stored in the CPC buffers. It can be accessed as a form of SMPL record that is an array of uint64_t objects by using cpc_buf_smpl_get_record() and cpc_buf_smpl_get_item(). How many record items are contained in a SMPL record and what kind of record items are included in the SMPL record are platform dependent. The format of the SMPL record is the layout of record items within a record. The format of the SMPL record is common among any SMPL events and any SMPL performance counters on the same processor. The validity of the kind of record items included in the SMPL record are may vary depending on the type of SMPL performance counter used and the type of SMPL event that is requested. The cpc_walk_smpl_recitems() function is used to determine the kind of record items that are contained in the SMPL record on this processor. And, cpc_walk_smpl_recitems_req() function is used to determine the valid record items in the SMPL record for a certain SMPL request.

The cpc_walk_smpl_recitems() function calls the action function on each item in the SMPL record. name is the name string of the SMPL record item. record_item_index is the integer value index to refer the item in the SMPL record.

The cpc_walk_smpl_recitems_req() function calls action function on each item in the SMPL record supported by the SMPL request specified by set and request_index_name is the name string of the SMPL record item. record_item_index is the integer value index to refer the item in the SMPL record.

The cpc_get_smpl_max_rec_count() function returns the maximum number of SMPL records per a request supported by the kernel for the sampling hardware on the processor into the uint_t object pointed to by max_rec_count. The request indicates that one performance monitoring request is added by cpc_set_add_request(). When adding a SMPL request using cpc_set_add_request(), the application needs to specify the number of SMPL records that should be collected for the request, using smpl_nrecs attribute. The kernel limits the maximum number of SMPL records for one request that can be returned to the application at one time, depending on the underlying sampling hardware. The cpc_get_smpl_max_rec_count() returns the maximum number that can be specified to smpl_nrecs attribute.

Return Values

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

The cpc_smpl_iname () function always returns a printable description of the hardware sampling implementation available on the processor.

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_smpl_npic() function always returns the number of performance counters for SMPL 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_all_common(), cpc_walk_events_pic(), cpc_walk_events_pic_common(), cpc_walk_attrs(), cpc_walk_attrs_common(), cpc_walk_generic_events_pic(), cpc_walk_smpl_recitems(), and cpc_walk_smpl_recitems_req() functions set errno to indicate the error.

The cpc_get_smpl_max_rec_count() sets errno to EINVAL and returns -1 if cpc was not successfully opened for SMPL. Otherwise, cpc_get_smpl_max_rec_count () returns 0.

Errors

The cpc_walk_events_all (), cpc_walk_events_all_common(), cpc_walk_events_pic (), cpc_walk_events_pic_common(), cpc_walk_attrs (), cpc_walk_attrs_common(), cpc_walk_generic_events_pic (), cpc_walk_smpl_recitems(), and cpc_walk_smpl_recitems_req () functions will fail if:

ENOMEM

There is not enough memory available.

The cpc_get_smpl_max_rec_count() function will fail if:

EINVAL

CPC was not successfully opened with SMPL.

Attributes

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

ATTRIBUTE TYPE
ATTRIBUTE VALUE
Interface Stability
Committed
MT-Level
Safe

See Also

cpc_bind_curlwp(3CPC), generic_events(3CPC), libcpc (3LIB), attributes(5)