perfstat_process_util Subroutine
Purpose
Calculates process utilization metrics.
Library
perfstat library (libperfstat.a)
Syntax
#include <libperfstat.h>perfstat_id_t * data;
perfstat_process_t * userbuff;
int sizeof_userbuff ;
int desired_number ;
Description
The perfstat_process_util subroutine provides the interface for process utilization metrics. The perfstat_process subroutine retrieves one or more process statistics to populate the perfstat_process_t data structure. The perfstat_process_util subroutine uses the current and previous values to calculate the utilization-related metrics. If the name and userbuff parameters are set to NULL, and the sizeof_userbuff parameter is set to 0, then the size of the current version of the perfstat_process_t data structure is returned. If the desired_number parameter is set to 0, the number of current elements, from the perfstat_rawdata_t data structure, is returned.
Parameters
| Item | Description |
|---|---|
| data | Specifies that the data parameter is of the type perfstat_rawdata_t. The perfstat_rawdata_t data structure can take the current and the previous values to calculate the utilization-related metrics. |
| userbuff | Specifies the memory area to be filled with one or more perfstat_process_t data structures. |
| sizeof_userbuff | Specifies the size of the perfstat_process_t data structure. Note: To obtain the size of the latest version of the
data structure perfstat_process_t, set the parameter sizeof_userbuff to
0, and the parameters name and userbuff to NULL.
|
| desired_number | Specifies the number of the perfstat_process_t structures to copy to the userbuff parameter. |
Return Values
Unless the perfstat_process_util subroutine is used to retrieve the number of available structures, the number of structures filled is returned upon successful completion. If unsuccessful, a value of -1 is returned and the errno global variable is set.
Error Codes
The perfstat_process_util subroutine is unsuccessful if the following error code is true:
| Item | Description |
|---|---|
| EINVAL | One of the parameters is not valid. |
Files
The libperfstat.h file defines standard macros, data types, and subroutines.