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$FreeBSD: head/lib/libgeom/libgeom.3 110545 2003-02-08 15:15:56Z phk $
.Dd February 8, 2003 .Dt LIBGEOM 3 .Os .Sh NAME .Nm geom_stats_open , .Nm geom_stats_close , .Nm geom_stats_resync , .Nm geom_stats_snapshot_get , .Nm geom_stats_snapshot_free , .Nm geom_stats_snapshot_timestamp , .Nm geom_stats_snapshot_reset , .Nm geom_stats_snapshot_next .Sh LIBRARY .Lb geom .Sh SYNOPSIS n libgeom.h .Ss "Statistics functions" .Ft void .Fn geom_stats_close void .Ft int .Fn geom_stats_open void .Ft void .Fn geom_stats_resync void .Ft void * .Fn geom_stats_snapshot_get void .Ft void .Fn geom_stats_snapshot_free "void *arg" .Ft void .Fn geom_stats_snapshot_timestamp "void *arg" "struct timespec *tp" .Ft void .Fn geom_stats_snapshot_reset "void *arg" .Ft struct g_stat * .Fn geom_stats_snapshot_next "void *arg" .Sh DESCRIPTION .Nm Libgeom is the library which contains the official and publicized API for interacting with the GEOM subsystem in the kernel. .Ss "Statistics functions" 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.
p The .Nm geom_stats_open and .Nm geom_stats_close functions opens and closes 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 filedescriptors locally. .Nm geom_stats_open returns zero on success, and sets errno if not.
p The .Nm geom_stats_resync function will check if more statistics collection points have been added in the kernel since .Nm geom_stats_open or the previous call to .Nm geom_stats_resync .
p .Nm geom_stats_snapshot_get will aquire 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 .Nm geom_stats_snapshot_free function. .Nm geom_stats_snapshot_get returns NULL on failure.
p .Nm geom_stats_snapshot_timestamp provides access to the timestamp aquired in the snapshot.
p .Nm geom_stats_snapshot_reset and .Nm geom_stats_snapshot_next provides an iterator over the statistics slots in the snapshot. .Nm geom_stats_snapshot_reset forces the internal pointer in the snapshot back to before the first item. .Nm geom_stats_snapshot_next returns the next item and NULL if there are no more items in the snapshot. .Sh AUTHORS .An Poul-Henning Kamp Aq phk@FreeBSD.org .Sh HISTORY .Nm geom library appeard in .Fx 5.1 .