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Set zstd as the default compression method for kdump initrd

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resolves: bz1896698
upstream: fedora
conflict: none

commit 0311f6e25b
Author: Tao Liu <ltao@redhat.com>
Date:   Wed Jan 5 17:42:12 2022 +0800

    Set zstd as the default compression method for kdump initrd

    zstd has better compression ratio and time consumption balance.
    When no customized compression method specified in kdump.conf,
    we will use zstd as the default compression method.

    **The test method:

    I installed kexec-tools with and without the patch, executing the following
    command for 4 times, and calculate the averange time:

    $ rm -f /boot/initramfs-*kdump.img && time kdumpctl rebuild && \
      ls -ail /boot/initramfs-*kdump.img

    **The test result:

    Bare metal x86_64 machine:
            dracut with squash module
             zlib     lzo      xz       lz4        zstd
    real     10.6282  11.0398  11.395   8.6424    10.1676
    user      9.8932  11.9072  14.2304  2.8286     8.6468
    sys       3.523    3.4626   3.6028  3.5        3.4942
    size of
    kdump.img 30575616 31419392 27102208 36666368 29236224

            dracut without squash module
            zlib      lzo      xz       lz4        zstd
    real     9.509    19.4876  11.6724  9.0338    10.267
    user    10.6028   14.516   17.8662  4.0476     9.0936
    sys      2.942     2.9184   3.0662  2.9232     3.0662
    size of
    kdump.img 19247949 19958120 14505056 21112544 17007764

    PowerVM hosted ppc64le VM:
            dracut with squash module | dracut without sqaush module
             zlib        zstd         |  zlib          zstd
    real     10.6742     10.7572      |   9.7676       10.5722
    user     18.754      19.8338      |  20.7932       13.179
    sys       1.8358      1.864       |   1.637         1.663
                                      |
    size of                           |
    kdump.img 36917248   35467264     |  21441323      19007108

    **discussion

    zstd has a better compression ratio and time consumption balance.

    Acked-by: Coiby Xu <coxu@redhat.com>
    Signed-off-by: Tao Liu <ltao@redhat.com>

Signed-off-by: Tao Liu <ltao@redhat.com>
This commit is contained in:
Tao Liu 2022-01-06 14:23:41 +08:00
parent 90223d3c71
commit 96dc819c25
4 changed files with 15 additions and 0 deletions
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6
kdump-lib.sh
View File

@ -443,6 +443,12 @@ is_wdt_active()
return 1
}
have_compression_in_dracut_args()
{
[[ "$(kdump_get_conf_val dracut_args)" =~ \
(^|[[:space:]])--(gzip|bzip2|lzma|xz|lzo|lz4|zstd|no-compress|compress)([[:space:]]|$) ]]
}
# If "dracut_args" contains "--mount" information, use it
# directly without any check(users are expected to ensure
# its correctness).

1
kexec-tools.spec
View File

@ -71,6 +71,7 @@ Requires: dracut >= 050
Requires: dracut-network >= 050
Requires: dracut-squash >= 050
Requires: ethtool
Requires: zstd
Recommends: grubby
BuildRequires: make
BuildRequires: zlib-devel elfutils-devel glib2-devel bzip2-devel ncurses-devel bison flex lzo-devel snappy-devel libzstd-devel

4
mkdumprd
View File

@ -431,6 +431,10 @@ done <<< "$(kdump_read_conf)"
handle_default_dump_target
if ! have_compression_in_dracut_args; then
add_dracut_arg "--compress" "zstd"
fi
if [[ -n $extra_modules ]]; then
add_dracut_arg "--add-drivers" "$extra_modules"
fi

4
mkfadumprd
View File

@ -62,6 +62,10 @@ if is_squash_available; then
_dracut_isolate_args+=(--add squash)
fi
if ! have_compression_in_dracut_args; then
_dracut_isolate_args+=(--compress zstd)
fi
if ! dracut --force --quiet "${_dracut_isolate_args[@]}" "$@" "$TARGET_INITRD"; then
perror_exit "mkfadumprd: failed to setup '$TARGET_INITRD' with dump capture capability"
fi