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 if the is_present field is set to 1. Event identifiers are not guaranteed contiguous. In other words, it is not because nevents is equal to 100, that event identifiers go from 0 to 99. The iterator function pfm_get_event_next() must be used to go from one identifier to the next.
- 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.