freebsd-nq/cmd/zfs/zfs_iter.h
Pawel Jakub Dawidek 0cee24064a Speed up 'zfs list -t snapshot -o name -s name'
FreeBSD #xxx:  Dramatically optimize listing snapshots when user
requests only snapshot names and wants to sort them by name, ie.
when executes:

  # zfs list -t snapshot -o name -s name

Because only name is needed we don't have to read all snapshot
properties.

Below you can find how long does it take to list 34509 snapshots
from a single disk pool before and after this change with cold and
warm cache:

    before:

        # time zfs list -t snapshot -o name -s name > /dev/null
        cold cache: 525s
        warm cache: 218s

    after:

        # time zfs list -t snapshot -o name -s name > /dev/null
        cold cache: 1.7s
        warm cache: 1.1s

NOTE: This patch only appears in FreeBSD.  If/when Illumos picks up
the change we may want to drop this patch and adopt their version.
However, for now this addresses a real issue.

Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #450
2012-06-14 09:49:04 -07:00

59 lines
1.8 KiB
C

/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2009 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#ifndef ZFS_ITER_H
#define ZFS_ITER_H
#ifdef __cplusplus
extern "C" {
#endif
typedef struct zfs_sort_column {
struct zfs_sort_column *sc_next;
struct zfs_sort_column *sc_last;
zfs_prop_t sc_prop;
char *sc_user_prop;
boolean_t sc_reverse;
} zfs_sort_column_t;
#define ZFS_ITER_RECURSE (1 << 0)
#define ZFS_ITER_ARGS_CAN_BE_PATHS (1 << 1)
#define ZFS_ITER_PROP_LISTSNAPS (1 << 2)
#define ZFS_ITER_DEPTH_LIMIT (1 << 3)
#define ZFS_ITER_RECVD_PROPS (1 << 4)
#define ZFS_ITER_SIMPLE (1 << 5)
int zfs_for_each(int, char **, int options, zfs_type_t,
zfs_sort_column_t *, zprop_list_t **, int, zfs_iter_f, void *);
int zfs_add_sort_column(zfs_sort_column_t **, const char *, boolean_t);
void zfs_free_sort_columns(zfs_sort_column_t *);
int zfs_sort_only_by_name(const zfs_sort_column_t *);
#ifdef __cplusplus
}
#endif
#endif /* ZFS_ITER_H */