PAPI_start (3) - Linux Manuals

NAME

PAPI_start -

Start counting hardware events in an event set.

SYNOPSIS

Detailed Description

C Interface:

#include <papi.h>

 int PAPI_start( int  EventSet );

Parameters:

EventSet -- an integer handle for a PAPI event set as created by PAPI_create_eventset

Return values:

PAPI_OK
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 EventSet specified does not exist.
PAPI_EISRUN -- The EventSet is currently counting events.
PAPI_ECNFLCT -- The underlying counter hardware can not count this event and other events in the EventSet simultaneously.
PAPI_ENOEVNT -- The PAPI preset is not available on the underlying hardware.

PAPI_start starts counting all of the hardware events contained in the previously defined EventSet. All counters are implicitly set to zero before counting. Assumes an initialized PAPI library and a properly added event set.

Example:

*  int EventSet = PAPI_NULL;
*  long long values[2];
*  int ret;
*  
*  ret = PAPI_create_eventset(&EventSet);
*  if (ret != PAPI_OK) handle_error(ret);
*  
*  // Add Total Instructions Executed to our EventSet
*  ret = PAPI_add_event(EventSet, PAPI_TOT_INS);
*  if (ret != PAPI_OK) handle_error(ret);
*  
*  // Start counting
*  ret = PAPI_start(EventSet);
*  if (ret != PAPI_OK) handle_error(ret);
*  poorly_tuned_function();
*  ret = PAPI_stop(EventSet, values);
*  if (ret != PAPI_OK) handle_error(ret);
*  printf("%lld\n",values[0]);
*  

See Also:

PAPI_create_eventset PAPI_add_event PAPI_stop

Author

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