PAPI System Information

• Executable Information
• Hardware Information
• Substrate Information

Executable Information

Information about the executable’s address space can be obtained by using the following low-level function:

C:

PAPI_get_executable_info()

Fortran:

PAPIF_get_exe_info(fullname, name, text_start, text_end, data_start, data_end,
                   bss_start, bss_end, lib_preload_env, check)

Arguments

The following arguments are implicit in the structure returned by the C function, or explicitly returned by Fortran:

• fullname -- fully qualified path + filename of the executable
• name -- filename of the executable with no path information
• text_start, text_end -- Start and End addresses of program text segment
• data_start, data_end -- Start and End addresses of program data segment
• bss_start, bss_end -- Start and End addresses of program bss segment
• lib_preload_env -- environment variable for preloading libraries

Note that the arguments text_start and text_end are the only fields that are filled on every architecture.

In C, this function returns a pointer to a structure containing information about the current program, such as the start and end addresses of the text, data, and bss segments.

In Fortran, the fields of the structure are returned explicitly.

In the following code example, PAPI_get_executable_info is used to acquire information about the start and end addresses of the program’s text segment:

#include <papi.h>
#include <stdio.h>

main()
{
    const PAPI_exe_info_t *prginfo = NULL;

    if (PAPI_library_init(PAPI_VER_CURRENT) != PAPI_VER_CURRENT)
    exit(1);

    if ((prginfo = PAPI_get_executable_info()) == NULL)
    exit(1);

    printf("Start of user program is at %p\n",prginfo->text_start);
    printf("End of user program is at %p\n",prginfo->text_end);
}

Possible Output

Start of user program is at 0x4000000000000f20
End of user program is at 0x4000000000034e00

In C, on success, the function returns a non-NULL pointer and on error, NULL is returned.

In Fortran, on success, the function returns PAPI_OK and on error, a non-zero error code is returned.

Hardware Information

Information about the system hardware can be obtained by using the following low-level function:

C:

PAPI_get_hardware_info()

Fortran:

PAPIF_get_hardware_info (ncpu, nnodes, totalcpus, vendor, vendor_string,
                         model, model_string, revision, mhz)

Arguments

The following arguments are implicit in the structure returned by the C function, or explicitly returned by Fortran.

• ncpu -- number of CPUs in an SMP Node
• nnodes -- number of Nodes in the entire system
• totalcpus -- total number of CPUs in the entire system
• vendor -- vendor id number of CPU
• vendor_string -- vendor id string of CPU
• model -- model number of CPU
• model_string -- model string of CPU
• revision -- Revision number of CPU
• mhz -- Cycle time of this CPU; may be an estimate generated at initialization time with a quick timing routine

In C, this function returns a pointer to a structure containing information about the hardware on which the program runs, such as: the number of CPUs, CPU model information, and the cycle time of the CPU.

In Fortran, the fields of the structure are returned explicitly.

Note that if this function were called before PAPI_library_init, it would be undefined.

In the following code example, PAPI_get_hardware_info is used to acquire hardware information about the total number of CPUs and the cycle time of the CPU:

#include <papi.h>
#include <stdio.h>

main()
{
    const PAPI_hw_info_t *hwinfo = NULL;

    if (PAPI_library_init(PAPI_VER_CURRENT) != PAPI_VER_CURRENT)
    exit(1);

    if ((hwinfo = PAPI_get_hardware_info()) == NULL)
    exit(1);

    printf("%d CPUs at %f Mhz.\n",hwinfo->totalcpus,hwinfo->mhz);
}

Possible Output

1 CPUs at 733.000000 Mhz.

In C, on success, this function returns a non-NULL pointer and on error, NULL is returned.

In Fortran, on success, this function returns PAPI_OK and on error, a non-zero error code is returned.

Substrate Information

Implementation details about the current hardware dependent substrate can be obtained by using the following low-level function:

C:

PAPI_get_substrate_info()

Fortran:

This call is not implemented in the Fortran interface.

Arguments

In C, this function returns a pointer to a structure containing implementation details about the substrate currently in use, such as: the number of counters and multiplexed counters supported, the number of preset and native events available, and whether (and how) certain advanced features are supported. For more details, refer to the definition of the PAPI_substrate_info_t structure found in papi.h, or see the discussion under getting and setting options. Note: if this function is called before PAPI_library_init, its output is undefined.

In the following code example, PAPI_get_substrate_info is used to determine how many preset and native events can be counted for a given substrate:

#include <papi.h>   
#include <stdio.h>

main()
{
    const PAPI_substrate_info_t *subinfo = NULL;

    if (PAPI_library_init(PAPI_VER_CURRENT) != PAPI_VER_CURRENT)
        exit(1);

    if ((subinfo = PAPI_get_substrate_info()) == NULL)
        exit(1);

    printf("num_preset_events: %d\n",subinfo->num_preset_events);

    printf("num_native_events: %d\n",subinfo->num_native_events);
}

Possible Output

num_preset_events: 47
num_native_events: 193

On success, this function returns a non-NULL pointer and on error, NULL is returned.