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LIBPFM

NAME

pfm_get_pmu_info − get PMU information

SYNOPSIS

#include <perfmon/pfmlib.h>

int pfm_get_pmu_info(pfm_pmu_t pmu, pfm_pmu_info_t *info);

DESCRIPTION

This function returns in info information about a PMU model designated by its identifier in pmu.

The pfm_pmu_info structure is defined as follows:
typedef struct {
const char *name;
const char *desc;
pfm_pmu_t pmu;
pfm_pmu_type_t type;
int size;
int nevents;
int first_event;
int max_encoding;
int num_cntrs;
int num_fixed_cntrs;
struct {
int is_present:1;
int is_arch_default:1;
int is_core:1;
int is_uncore:1;
int reserved:28;
};
} pfm_pmu_info_t;

The fields of this structure are defined as follows:

name

This is the symbolic name of the PMU. This name can be used as a prefix in an event string. This is a read-only string.

desc

This is the description of PMU. This is a read-only string.

pmu

This is the unique PMU identification code. It is identical to the value passed in pmu and it provided only for completeness.

type

This field contains the type of the PMU. The following types are defined:

PFM_PMU_TYPE_UNKNOWN

The type of the PMU could not be determined.

PFM_PMU_TYPE_CORE

This field is set to one when the PMU is implemented by the processor core.

PFM_PMU_TYPE_UNCORE

This field is set to one when the PMU is implemented on the processor die but at the socket level, i.e., capturing events for all cores.

nevents

This is the number of available events for this PMU model based on the host processor. It is only valid is the is_present field is set to 1.

first_event

This field returns the opaque index of the first event for this PMU model. The index can be used with pfm_get_event_info() or pfm_get_event_next() functions. In case no event is available, this field contains -1.

num_cntrs

This field contains the number of generic counters supported by the PMU. A counter is generic if it can count more than one event. When it is not possible to determine the number of generic counters, this field contains -1.

num_fixed_cntrs

This field contains the number of fixed counters supported by the PMU. A counter is fixed if it hardwired to count only one event. When it is not possible to determine the number of generic counters, this field contains -1.

size

This field contains the size of the struct passed. This field is used to provide for extensibility of the struct without compromising backward compatibility. The value should be set to sizeof(pfm_pmu_info_t). If instead, a value of 0 is specified, the library assumes the struct passed is identical to the first ABI version which size is PFM_PMU_INFO_ABI0. Thus, if fields were added after the first ABI, they will not be set by the library. The library does check that bytes beyond what is implemented are zeroes.

max_encoding

This field returns the number of event codes returned by pfm_get_event_encoding().

is_present

This field is set to one is the PMU model has been detected on the host system.

is_dfl

This field is set to one if the PMU is the default PMU for this architecture. Otherwise this field is zero.

RETURN

If successful, the function returns PFM_SUCCESS and PMU information in info, otherwise it returns an error code.

ERRORS

PFMLIB_ERR_NOINIT

Library has not been initialized properly.

PFMLIB_ERR_NOTSUPP

PMU model is not supported by the library.

PFMLIB_ERR_INVAL

The pmu argument is invalid or info is NULL or size is not zero.

AUTHOR

Stephane Eranian <eranian AT gmail DOT com>

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