perfstat_memory_page Subroutine
Purpose
Retrieves usage statistics for multiple page sizes.
Library
Perfstat Library (libperfstat.a)
Syntax
#include <libperfstat.h>
int perfstat_memory_page ( psize, userbuff, sizeof_userbuff, desired_number )
perfstat_psize_t *psize;
perfstat_memory_total_wpar_t *userbuff;
size_t sizeof_userbuff;
int desired_number;Description
The perfstat_memory_page subroutine returns the statistics corresponding to the different page sizes.
To get the number of supported page sizes, the psize parameter and the userbuff parameter must be specified as NULL, and the value of the desired_number parameter must be set to zero.
To get the statistics for the supported page sizes, specify the page size in the psize parameter. The desired_number parameter specifies the number of different page size statistics to be collected. The userbuff parameter must be allocated.
Parameters
| Item | Description |
|---|---|
| psize | Specifies the page size for which the statistics are to be collected. |
| userbuff | Points to the memory area that is to be filled with the perfstat_memory_page_t structure. |
| sizeof_userbuff | Specifies the size of the perfstat_memory_page_t structure. |
| desired_number | Specifies the number of different page size statistics to be collected. |
Return Values
Upon successful completion the number of perfstat_memory_page_t structures that are filled is returned. If the specified page size is not used, the returned value is 0. For example, if a user specified 4K page size, the return value is 0 since the specified page size is not used.
If unsuccessful, a value of -1 is returned, and the errno global variable is set.
Error Codes
The perfstat_memory_page subroutine is unsuccessful if the following is true:
| Item | Description |
|---|---|
| EINVAL | One of the parameters is not valid |
Files
The libperfstat.h file defines standard macros, data types, and subroutines.