поиск масок событий (search for an event masks)
Имя (Name)
pfm_find_event - search for an event masks
Синопсис (Synopsis)
#include <perfmon/pfmlib.h>
int pfm_find_event(const char *str);
Описание (Description)
This function is used to convert an event string passed in str
into an opaque event identifier, i.e., the return value.
Events are first manipulated a strings which contain the event
name, sub-event names and optional filters and modifiers. This
function analyzes the string and try to find the matching event.
The event string is a structured string and it is composed as
follows:
[pmu_name::]event_name[:unit_mask][:modifier|:modifier=val]
The various components are separated by : or ::, they are defined
as follows:
pmu_name
This is an optional prefix to designate a specific PMU
model. With the prefix the event which matches the
event_name is used. In case multiple PMU models are
activated, there may be conflict with identical event
names to mean the same or different things. In that case,
it is necessary to fully specify the event with a
pmu_name. That string corresponds to what is returned by
pfm_get_pmu_name().
event_name
This is the event name and is required. The library is not
case sensitive on event string. The event name must match
completely the actual event name; it cannot be a
substring.
unit_mask
The optional unit mask which can be considered like a sub-
event of the major event. If a event has unit masks, and
there is no default, then at least one unit mask must be
passed in the string. Multiple unit masks may be specified
for a single event.
modifier
A modifier is an optional filter which is provided by the
hardware register hosting the event or by the underlying
kernel infrastructure. Typical modifiers include
privilege level filters. Some modifiers are simple
boolean, in which case just passing their names is
equivalent to setting their value to true. Other modifiers
need a specific value, in which case it is provided after
the equal sign. No space is tolerate around the equal
sign. The list of modifiers depends on the host PMU and
underlying kernel API. They are documented in PMU-specific
documentation. Multiple modifiers may be passed. There is
not order between unit masks and modifiers.
The library uses the generic term attribute to designate both
unit masks and modifiers.
Here are a few examples of event strings:
amd64::RETIRED_INSTRUCTIONS:u
Event RETIRED_INSTRUCTION on AMD64 processor, measure at
user privilege level only
RS_UOPS_DISPATCHED:c=1:i:u
Event RS_UOPS_DISPATCHED measured at user privilege level
only, and with counter-mask set to 1
For the purpose of this function, only the pmu_name and
event_name are considered, everything else is parsed, thus must
be valid, but is ignored.
The function searches only for one event per call. As a
convenience, the function will identify the event up to the first
comma. In other words, if str is equal to "EVENTA,EVENTB", then
the function will only look at EVENTA and will not return an
error because of invalid event string. This is handy when parsing
constant event strings containing multiple, comma-separated,
events.
Возврат (Return)
The function returns the opaque event identifier that corresponds
that the event string. In case of error, a negative error code is
returned instead.
Ошибки (Error)
PFMLIB_ERR_NOINIT
The library has not been initialized properly.
PFMLIB_ERR_INVAL
The event string is NULL.
PFMLIB_ERR_NOMEM
The library ran out of memory.
PFMLIB_ERR_NOTFOUND
The event was not found
PFMLIB_ERR_ATTR
Invalid event attribute
PFMLIB_ERR_ATTR_VAL
Invalid event attribute value
PFMLIB_ERR_TOOMANY
Too many event attributes passed
