NAME

SYNOPSIS

#include <perfmon/pfmlib.h>
#include <perfmon/pfmlib_i386_p6.h>

DESCRIPTION

The libpfm library provides full support for the P6 processor family, including the Pentium M processor. The interface is defined in pfmlib_i386_p6.h. It consists of a set of functions and structures which describe and allow access to the P6 processors specific PMU features.

When P6 processor specific features are needed to support a measurement, their descriptions must be passed as model-specific input arguments to the pfm_dispatch_events call. The P6 processors specific input arguments are described in the pfmlib_i386_p6_input_param_t structure and the output parameters in pfmlib_i386_p6_output_param_t. They are defined as follows:

typedef struct {
        unsigned int    cnt_mask;
        unsigned int    flags;
} pfmlib_i386_p6_counter_t;

typedef struct {
        pfmlib_i386_p6_counter_t        pfp_i386_p6_counters[PMU_I386_P6_NUM_COUNTERS];
        uint64_t                        reserved[4];
} pfmlib_i386_p6_input_param_t;

typedef struct {
        uint64_t        reserved[8];
} pfmlib_i386_p6_output_param_t;

The P6 processor provides a few additional per-event features for counters: thresholding, inversion, edge detection. They can be set using the pfp_i386_p6_counters data structure for each event. The flags field can be initialized as follows:

• PFMLIB_I386_P6_SEL_INV: Inverse the results of the cnt_mask comparison when set
• PFMLIB_I386_P6_SEL_EDGE: Enables edge detection of events

The cnt_mask field contains 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. When zero all occurrences are counted.

Handling of Pentium M

The library provides full support for the Pentium M PMU. A Pentium implements more events than a generic P6 processor. The library autodetects the host processor and can distinguish generic P6 processor from a Pentium. Thus no special call is needed.

ERRORS

SEE ALSO

AUTHOR