perfstat_process Subroutine

Purpose

Retrieves process utilization metrics.

Library

perfstat library (libperfstat.a)

Syntax

#include <libperfstat.h>

int perfstat_process (name, userbuff, sizeof_userbuff, desired_elements)
perfstat_id_t * name;
perfstat_process_t * userbuff;
int sizeof_userbuff;
int desired_number;

Description

The perfstat_process subroutine is the interface for per process utilization metrics. The perfstat_process subroutine retrieves one or more process statistics to populate the perfstat_process_t data structure. If the name and userbuff parameters are specified as NULL, and the desired_elements parameter is stated as 0, the perfstat_process subroutine returns the number of active-processes, excluding the waiting processes. 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.

Note: To improve performance, the collection of process scope disk statistics is disabled by default. To enable the collection of this data, enter the following command:

schedo -p -o proc_disk_stats=1

Parameters

Table 1. Parameters
Item	Description
`name`	Determines whether the statistics must be captured for all the processes or for a specific process. The `name` parameter must be set to NULL to obtain the statistics for all processes. For a specific process, the process ID must be mentioned. Note: The process ID must be passed as a string. For example, to retrieve the statistics for a process with process ID 5478, the `name` parameter must be set to 5478.
`userbuff`	Points to the memory area that is 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 `perfstat_process_t` data structure, set the `sizeof_userbuff` parameter to 0, and `name` and `userbuff` parameter to NULL.
`desired_elements`	Specifies the number of `perfstat_process_t` data structures to copy to the `userbuff` parameter.

Return Values

Unless the perfstat_process subroutine is used to retrieve the number of available structures, the number of structures that are 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 subroutine is unsuccessful if the following error code is true:

Table 2. Error Codes
Item	Description
`EINVAL`	One of the parameters is not valid.

Files

The libperfstat.h file defines standard macros, data types, and subroutines.