NAME

SYNOPSIS

#include <perfmon/pfmlib.h>

int pfm_get_os_event_encoding(const char *str, int dfl_plm, pfm_os_t os,  void *arg);

DESCRIPTION

The event string may contains sub-event masks (umask) and any other supported modifiers. Only one event is parsed from the string. For convenience, it is possible to pass a comma-separated list of events in str but only the first event is encoded.

The following values are supported for os:

PFM_OS_NONE

This value causes the event to be encoded purely as specified by the PMU hardware. The arg argument must be a pointer to a pfm_pmu_encode_arg_t structure which is defined as follows:

typedef struct {
    uint64_t    *codes;
    char        **fstr;
    size_t      size;
    int         count;
    int         idx;
} pfm_pmu_encode_arg_t;

The fields are defined as follows:

codes

A pointer to an array of 64-bit values. On input, if codes is NULL, then the library allocates whatever is necessary to store the encoding of the event. If codes is not NULL on input, then count must reflect its actual number of elements. If count is big enough, the library stores the encoding at the address provided. Otherwise, an error is returned.

count

On input, the field contains the maximum number of elements in the array codes. Upon return, it contains the number of actual entries in codes. If codes is NULL, then count must be zero.

fstr

If the caller is interested in retrieving the fully qualified event string where all used unit masks and all modifiers are spelled out, this field must be set to a non-null address of a pointer to a string. Upon return, if fstr was not NULL on entry, then it points to the event string. The string is dynamically allocated and needs to eventually be freed. If fstr was NULL on entry, then nothing is returned in this field.

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_encode_arg_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_RAW_ENCODE_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.

idx

Upon return, this field contains the opaque unique identifier for the event described in str. This index can be used to retrieve information about the event using pfm_get_event_info(), for instance.

PFM_OS_PERF_EVENT, PFM_OS_PERF_EVENT_EXT

This value causes the event to be encoded for the perf_event Linux kernel interface (available since 2.6.31). The arg must be a pointer to a pfm_perf_encode_arg_t structure. The PFM_OS_PERF_EVENT layer provides the modifiers exported by the underlying PMU hardware, some of which may actually be overridden by the perf_event interface, such as the monitoring privilege levels. The PFM_OS_PERF_EVENT_EXT extends PFM__OS_PERF_EVENT to add modifiers controlled only by the perf_event interface, such as sampling period or frequency.

typedef struct {
    struct perf_event_attr *attr;
    char **fstr;
    size_t size;
    int idx;
    int cpu;
    int flags;
} pfm_perf_encode_arg_t;

The fields are defined as follows:

attr

A pointer to a struct perf_event_attr as defined in perf_event.h. This field cannot be NULL on entry. The struct is reset by the call.

fstr

If the caller is interested in retrieving the fully qualified event string where all used unit masks and all modifiers are spelled out, this field must be set to a non-null address of a pointer to a string. Upon return, if fstr was not NULL on entry, then it points to the event string. The string is dynamically allocated and needs to eventually be freed. If fstr was NULL on entry, then nothing is returned in this field.

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_perf_encode_arg_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_PERF_ENCODE_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.

idx

Upon return, this field contains the opaque unique identifier for the event described in str. This index can be used to retrieve information about the event using pfm_get_event_info(), for instance.

cpu

Not used yet.

flags

Not used yet.

Here is a example of how this function could be used with PERF_OS_NONE:

#include <inttypes.h>
#include <err.h>
#include <perfmon/pfmlib.h>
int main(int argc, char **argv)
{
   pfm_pmu_encode_t arg;
   int ret;

   ret = pfm_initialize();
   if (ret != PFMLIB_SUCCESS)
      errx(1, "cannot initialize library %s", pfm_strerror(ret));

   memset(&arg, 0, sizeof(arg));

   ret = pfm_get_os_event_encoding("RETIRED_INSTRUCTIONS", PFM_PLM3, PFM_OS_NONE, &arg);
   if (ret != PFM_SUCCESS)
      err(1", cannot get encoding %s", pfm_strerror(ret));

   for(i=0; i < arg.count; i++)
      printf("count[%d]=0x%"PRIx64"\n", i, arg.codes[i]);

   free(arg.codes);
   return 0;
}

RETURN

ERRORS

PFM_ERR_TOOSMALL

The code argument is too small for the encoding.

PFM_ERR_INVAL

The code or count argument is NULL.

PFM_ERR_NOMEM

Not enough memory.

PFM_ERR_NOTFOUND

Event not found.

PFM_ERR_ATTR

Invalid event attribute (unit mask or modifier)

PFM_ERR_ATTR_VAL

Invalid modifier value.

PFM_ERR_ATTR_SET

attribute already set, cannot be changed.

PFM_ERR_ATTR_UMASK

Missing unit mask.

PFM_ERR_ATTR_FEATCOMB

Unit masks or features cannot be combined into a single event.

AUTHOR

Index

NAME

SYNOPSIS

DESCRIPTION

RETURN

ERRORS

AUTHOR