PAPI_read - Online Linux Manual Page

Section : 3
Updated : September, 2004
Source : PAPI Programmer's Reference
Note : PAPI

NAME

PAPI_read − read hardware counters from an event set

PAPI_accum − accumulate and reset counters in an event set

SYNOPSIS

C Interface

#include <papi.h>

int PAPI_read(int

EventSet

, long_long *

values

);

int PAPI_accum(int

EventSet

, long_long *

values

);

Fortran Interface

#include "fpapi.h"

PAPIF_read(C_INT

EventSet,

C_LONG_LONG(*)

values,

C_INT

check

)

PAPIF_accum(C_INT

EventSet,

C_LONG_LONG(*)

values,

C_INT

check

)

DESCRIPTION

These calls assume an initialized PAPI library and a properly added event set. PAPI_read() copies the counters of the indicated event set into the array values. The counters continue counting after the read.

PAPI_accum() adds the counters of the indicated event set into the array values. The counters are zeroed and continue counting after the operation.

Note the differences between PAPI_read() and PAPI_accum(), specifically that PAPI_accum() resets the values array to zero.

ARGUMENTS

EventSet -- an integer handle for a PAPI Event Set as created by

PAPI_create_eventset(3)

*values -- an array to hold the counter values of the counting events

RETURN VALUES

On success, these functions return PAPI_OK."
On error, a non-zero error code is returned.

ERRORS

PAPI_EINVAL"

One or more of the arguments is invalid.

PAPI_ESYS"

A system or C library call failed inside PAPI, see the errno" variable.

PAPI_ENOEVST"

The event set specified does not exist.

EXAMPLES

  do_100events();
  if (PAPI_read(EventSet, values) != PAPI_OK)
    handle_error(1);
  /* values[0] now equals 100 */
  do_100events();
  if (PAPI_accum(EventSet, values) != PAPI_OK)
    handle_error(1);
  /* values[0] now equals 200 */
  values[0] = -100;
  do_100events();
  if (PAPI_accum(EventSet, values) != PAPI_OK)
    handle_error(1);
  /* values[0] now equals 0 */

BUGS

These functions have no known bugs.