LIBPFM(3) Linux Programmer's Manual LIBPFM(3)NAMElibpfm_core - support for Intel Core processor family
SYNOPSIS
#include <perfmon/pfmlib.h>
#include <perfmon/pfmlib_core.h>
DESCRIPTION
The libpfm library provides full support for the Intel Core processor
family, including the Core 2 Duo and Quad series. The interface is
defined in pfmlib_core.h. It consists of a set of functions and struc‐
tures which describe and allow access to the Intel Core processors spe‐
cific PMU features.
When Intel Core processor specific features are needed to support a
measurement, their descriptions must be passed as model-specific input
arguments to the pfm_dispatch_events() function. The Intel Core proces‐
sors specific input arguments are described in the pfm‐
lib_core_input_param_t structure. No output parameters are currently
defined. The input parameters are defined as follows:
typedef struct {
unsigned int cnt_mask;
unsigned int flags;
} pfmlib_core_counter_t;
typedef struct {
unsigned int pebs_used;
} pfmlib_core_pebs_t;
typedef struct {
pfmlib_core_counter_t pfp_core_counters[PMU_CORE_NUM_COUNTERS];
pfmlib_core_pebs_t pfp_core_pebs;
uint64_t reserved[4];
} pfmlib_core_input_param_t;
The Intel Core processor provides a few additional per-event features
for counters: thresholding, inversion, edge detection. They can be set
using the pfp_core_counters data structure for each event. The flags
field can be initialized with any combinations of the following values:
PFMLIB_CORE_SEL_INV
Inverse the results of the cnt_mask comparison when set
PFMLIB_CORE_SEL_EDGE
Enables edge detection of events.
The cnt_mask field is used to set the event threshold. The value of
the counter is incremented each time the number of occurrences per
cycle of the event is greater or equal to the value of the field. Thus
the event is modified to actually measure the number of qualifying
cycles. When zero all occurrences are counted (this is the default).
Support for Precise-Event Based Sampling (PEBS)
The library can be used to setup the PMC registers when using PEBS. In
this case, the pfp_core_pebs structure must be used and the pebs_used
field must be set to 1. When using PEBS, it is not possible to use more
than one event.
Support for Intel Core 2 Duo and Quad processors
The Intel Core 2 Duo and Quad processors are based on the Intel Core
micro-architecture. They implement the Intel architectural PMU and
some extensions such as PEBS. They support all the architectural
events and a lot more Core 2 specific events. The library auto-detects
the processor and provides access to Core 2 events whenever possible.
ERRORS
Refer to the description of the pfm_dispatch_events() function for
errors.
SEE ALSOpfm_dispatch_events(3) and set of examples shipped with the library
AUTHOR
Stephane Eranian <eranian@hpl.hp.com>
November, 2006 LIBPFM(3)
