sg_get_disk_io_stats3

Usage

FC#include <statgrab.h>F[0]

Overview

The FCsg_get_disk_io_statsF[0] functions provide disk I/O statistics on a per disk basis. All get- and diff-functions take an optional FCentriesF[0] parameter, which points (when given) to a size_t to take the number of returned vector entries.

The FCsg_get_disk_io_statsF[0]() and FCsg_get_disk_io_stats_rF[0]() functions deliver the I/O-statistics since the disk has been attached to the system. The FCsg_get_disk_io_stats_diffF[0]() and FCsg_get_disk_io_stats_diff_betweenF[0]() deliver the difference between two calls of FCsg_get_disk_io_statsF[0]() or FCsg_get_disk_io_stats_rF[0](), respectively.

API Shortcut

FCsg_disk_io_statsF[0] vectors got from FCsg_get_disk_io_stats_rF[0]() or FCsg_get_disk_io_stats_diff_betweenF[0]() must be freed using FCsg_free_disk_io_statsF[0]() when not needed any more. The caller is responsible for doing it.

Additionally two support functions for FCqsortF[0](3) are available: FCsg_disk_io_compare_nameF[0]() and FCsg_disk_io_compare_trafficF[0]().

Example

FC
size_t entries;
sg_disk_io_stats *io_stats = NULL;
while( NULL != ( io_stats = sg_get_disk_io_stats_diff(&entries) ) ) {
    /* show disks with most traffic first */
    qsort( io_stats, entries, sizeof(io_stats[0]), &sg_disk_io_compare_traffic );
    show_disk_io_stats( io_stats );
}
        F[0]

On some platforms, such as Solaris 7, the kernel value is stored in a 32bit int, so wraps around when it reaches 4GB. Other platforms, such as Solaris 8 (and most other modern systems), hold the value in a 64bit int, which wraps somewhere near 17 million terabytes. The FCsg_get_disk_io_stats_diffF[0]() function and the FCsg_get_disk_io_stats_diff_betweenF[0]() function care about these overflows and try to detect overflows when the diff is calculated.

On Solaris libstatgrab will attempt to get the cXtXdXsX representation for the FCdisk_nameF[0] string. If it fails it will use a name like sd0. On some systems programs calling libstatgrab will need elevated privileges to lookup some of the names. The mappings are built up when FCsg_initF[0]() is called for the first time.

Return values

All diskio statistics return a pointer to a structure of type FCsg_disk_io_statsF[0].

FC
typedef struct {
        char *disk_name;
        unsigned long long read_bytes;
        unsigned long long write_bytes;
        time_t systime;
} sg_disk_io_stats;
    F[0]

FCdisk_nameF[0]

The name known to the operating system. (eg. on linux it might be hda)

FCread_bytesF[0]

The number of bytes the disk has read.

FCwrite_bytesF[0]

The number of bytes the disk has written.

FCsystimeF[0]

The time period over which FCread_bytesF[0] and FCwrite_bytesF[0] were transferred.

Website

⟨https://libstatgrab.org/⟩