freebsd-dev/cmd/zfs
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
..
.gitignore Add .gitignore files to exclude build products 2010-01-08 11:35:17 -08:00
Makefile.am Combine libraries: spl, avl, efi, share, unicode. 2012-01-17 15:19:50 -08:00
Makefile.in Linux 3.4 compat, d_make_root() replaces d_alloc_root() 2012-06-11 10:04:49 -07:00
zfs_iter.c Speed up 'zfs list -t snapshot -o name -s name' 2012-06-14 09:49:04 -07:00
zfs_iter.h Speed up 'zfs list -t snapshot -o name -s name' 2012-06-14 09:49:04 -07:00
zfs_main.c Speed up 'zfs list -t snapshot -o name -s name' 2012-06-14 09:49:04 -07:00
zfs_util.h Update core ZFS code from build 121 to build 141. 2010-05-28 13:45:14 -07:00