All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
3. The names of the authors may not be used to endorse or promote
products derived from this software without specific prior written
permission.
THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
SUCH DAMAGE.
$FreeBSD: head/lib/libgeom/libgeom.3 116549 2003-06-18 19:43:17Z charnier $
.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 .Nd userland API library for kernel GEOM subsystem .Sh LIBRARY .Lb libgeom .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 The .Nm geom library 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 .Fn geom_stats_open and .Fn 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 .Fn geom_stats_open function returns zero on success, and sets .Va errno if not.
p The .Fn geom_stats_resync function will check if more statistics collection points have been added in the kernel since .Fn geom_stats_open or the previous call to .Fn geom_stats_resync .
p The .Fn 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 .Fn geom_stats_snapshot_free function. The .Fn geom_stats_snapshot_get function returns .Dv NULL on failure.
p The .Fn geom_stats_snapshot_timestamp function provides access to the timestamp acquired in the snapshot.
p The .Fn geom_stats_snapshot_reset and .Fn geom_stats_snapshot_next functions provide an iterator over the statistics slots in the snapshot. The .Fn geom_stats_snapshot_reset function forces the internal pointer in the snapshot back to before the first item. The .Fn geom_stats_snapshot_next function returns the next item, and .Dv NULL if there are no more items in the snapshot. .Sh AUTHORS .An Poul-Henning Kamp Aq phk@FreeBSD.org .Sh HISTORY The .Nm geom library appeared in .Fx 5.1 .