NAME    [Toc]    [Back]

     geom_stats_open, geom_stats_close, geom_stats_resync,
     geom_stats_snapshot_get, geom_stats_snapshot_free,
     geom_stats_snapshot_timestamp, geom_stats_snapshot_reset,
     geom_stats_snapshot_next -- userland API library for kernel GEOM subsystem

LIBRARY    [Toc]    [Back]

     Userland API Library for kernel GEOM subsystem (libgeom, -lgeom)

SYNOPSIS    [Toc]    [Back]

     #include <libgeom.h>

   Statistics Functions    [Toc]    [Back]
     void
     geom_stats_close(void);

     int
     geom_stats_open(void);

     void
     geom_stats_resync(void);

     void *
     geom_stats_snapshot_get(void);

     void
     geom_stats_snapshot_free(void *arg);

     void
     geom_stats_snapshot_timestamp(void *arg, struct timespec *tp);

     void
     geom_stats_snapshot_reset(void *arg);

     struct g_stat *
     geom_stats_snapshot_next(void *arg);

DESCRIPTION    [Toc]    [Back]

     The geom library contains the official and publicized API for interacting
     with the GEOM subsystem in the kernel.

   Statistics Functions    [Toc]    [Back]
     GEOM collects statistics data for all consumers and providers, but does
     not perform any normalization or presentation on the raw data, this is
     left as an excercize for user-land presentation utilities.

     The geom_stats_open() and geom_stats_close() functions open and close the
     necessary pathways to access the raw statistics information in the kernel.
  These functions are likely to open one or more files and cache the
     file descriptors locally.	The geom_stats_open() function returns zero on
     success, and sets errno if not.

     The geom_stats_resync() function will check if more statistics collection
     points have been added in the kernel since geom_stats_open() or the previous
 call to geom_stats_resync().

     The geom_stats_snapshot_get() function will acquire a snapshot of the raw
     data from the kernel, and while a reasonable effort is made to make this
     snapshot as atomic and consistent as possible, no guarantee is given that
     it will actually be so.  The snapshot must be freed again using the
     geom_stats_snapshot_free() function.  The geom_stats_snapshot_get() function
 returns NULL on failure.

     The geom_stats_snapshot_timestamp() function provides access to the timestamp
 acquired in the snapshot.

     The geom_stats_snapshot_reset() and geom_stats_snapshot_next() functions
     provide an iterator over the statistics slots in the snapshot.  The
     geom_stats_snapshot_reset() function forces the internal pointer in the
     snapshot back to before the first item.  The geom_stats_snapshot_next()
     function returns the next item, and NULL if there are no more items in
     the snapshot.

AUTHORS    [Toc]    [Back]

     Poul-Henning Kamp <[email protected]>

HISTORY    [Toc]    [Back]

     The geom library appeared in FreeBSD 5.1.


FreeBSD 5.2.1		       February 8, 2003 		 FreeBSD 5.2.1