.TH LIBPFM 3  "August, 2006" "" "Linux Programmer's Manual"

.SH NAME

pfm_find_event, pfm_find_full_event, pfm_find_event_bycode,

pfm_find_event_bycode_next, pfm_find_event_mask \- search for events and unit

masks

.SH SYNOPSIS

.nf

.B #include <perfmon/pfmlib.h>

.sp

.BI "int pfm_find_event(const char *"str ", unsigned int *"desc ");"

.BI "int pfm_find_full_event(const char *"str ", pfmlib_event_t *"e ");"

.BI "int pfm_find_event_bycode(int "code ", unsigned int *"desc ");"

.BI "int pfm_find_event_bycode_next(unsigned int "desc1 ", int "code ", unsigned int *"desc ");"

.BI "int pfm_find_event_mask(unsigned int "idx ", const char *"str ", unsigned int *"mask_idx ");"

.sp

.SH DESCRIPTION

The PMU counters can be programmed to count the number of occurrences

of certain events. The number of events varies from one PMU model

to the other. Each event has a name and a code which is used to program

the actual PMU register. Some event may need to be further qualified

with unit masks.

.sp

The library does not directly expose the event code, nor unit mask code,

to user applications because it is not necessary. Instead applications

use names to query the library for particular information about events.

Given an event name, the library returns an opaque descriptor. 

Each descriptor is unique and has no relationship to the event code.

.sp

The set of functions described here can be used to get an event descriptor

given either the name of the event or its code. Several events may

share the same code. An event name is a string structured as: event_name[:unit_mask1[:unit_mask2]].

.sp

The \fBpfm_find_event()\fR function is a general purpose search routine.

Given an event name in \fBstr\fR, it returns the descriptor for the

corresponding event.  If unit masks are provided, they are not taken

into account. This function is being \fBdeprecated\fR in favor of

the \fBpfm_find_full_event()\fR function.

.sp

The \fBpfm_find_full_event()\fR function is the general purpose search routine.

Given an event name in \fBstr\fR, it returns in \fBev\fR, the full event descriptor that

includes the event descriptor in \fBev->event\fR and the unit mask descriptors

in \fBev->unit_masks\fR. The number of unit masks descriptors returned is

indicated in \fBev->num_masks\fR. Unit masks are specified as a colon

separated list of unit mask names, exact values or value combinations.

For instance, if event A supports unit masks M1 (0x1) and M2 (0x40), and

both unit masks are to be measured, then the following values for

\fBstr\fR are valid: "A:M1:M2", "A:M1:0x40", "A:M2:0x1", "A:0x1:0x40", "A:0x41".

.sp 

The \fBpfm_find_event_bycode()\fR function searches for an event given

its \fBcode\fR represented as an integer. It returns in \fBdesc\fR,

the event code. Unit masks are ignored.

.sp

Because there can be several events with the same code, the library

provides the \fBpfm_find_event_bycode_next()\fR function to search for other

events with the same code. Given an event \fBdesc1\fR and a \fBcode\fR,

this function will look for the next event with the same code. If

such an event exists, its descriptor will be stored into \fBdesc\fR.

It is not necessary to have called the \fBpfm_find_event_bycode()\fR function prior

to calling this function. This function is fully threadsafe as it does

not maintain any state between calls.

.sp

The \fBpfm_find_event_mask()\fR function is used to find the unit mask descriptor

based on its name or numerical value passed in \fBstr\fR for the event specified

in \fBidx\fR. The numeric value must be an exact match of an existing unit mask value,

i.e., all bits must match. Some events do not have unit masks, in which case this function

returns an error.

.SH RETURN

All functions return whether or not the call was successful.

A return value of \fBPFMLIB_SUCCESS\fR indicates success, 

otherwise the value is the error code.

.SH ERRORS

.B PFMLIB_ERR_NOINIT

the library has not been initialized properly.

.TP

.B PFMLIB_ERR_INVAL

the event descriptor is invalid, or the pointer argument is NULL.

.TP

.B PFMLIB_ERR_NOTFOUND

no matching event or unit mask was found.

.SH AUTHOR

Stephane Eranian <eranian@hpl.hp.com>

.PP