Hi Tao, You man need to add zstd as dependency as zstd is not installed by default judging from the following console log (tests/output/local-kdump/0-local.console) when running "RELEASE=34 make test-run", [ 6.678966] dracut[871]: *** Creating image file '/boot/initramfs-5.11.12-300.fc34.x86_64kdump.img' *** [ 6.694341] init.sh[3243]: /usr/bin/dracut: line 2386: zstd: command not found [ 6.695267] init.sh[3242]: cpio: write error: Broken pipe [ 6.697102] init.sh[846]: dracut: dracut: creation of /boot/initramfs-5.11.12-300.fc34.x86_64kdump.img failed [ 6.698063] dracut[871]: dracut: creation of /boot/initramfs-5.11.12-300.fc34.x86_64kdump.img failed [ 6.873014] init.sh[648]: kdump: mkdumprd: failed to make kdump initrd

On Tue, Jan 04, 2022 at 05:24:26PM +0800, Tao Liu wrote: >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. > >v1 -> v2: >Use kdump_get_conf_val() to get dracut_args values of kdump.conf > >v2 -> v3: >Attached testing benchmark > >v3 -> v4: >Re-measured and re-attached the testing benchmark of x86_64 and ppc64le. >Changed regex '.*[[:space:]]' to '(^|[[:space:]])' > >v4 -> v5: >Attached lzo/xz/lz4 testing benchmark. > >Signed-off-by: Tao Liu <ltao(a)redhat.com&gt; >--- > kdump-lib.sh | 6 ++++++ > mkdumprd | 4 ++++ > mkfadumprd | 4 ++++ > 3 files changed, 14 insertions(+) > >diff --git a/kdump-lib.sh b/kdump-lib.sh >index e435498..6d668a5 100755 >--- a/kdump-lib.sh >+++ b/kdump-lib.sh >@@ -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). >diff --git a/mkdumprd b/mkdumprd >index d87d588..9c26ecc 100644 >--- a/mkdumprd >+++ b/mkdumprd >@@ -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 >diff --git a/mkfadumprd b/mkfadumprd >index b890f83..16fdacc 100644 >--- a/mkfadumprd >+++ b/mkfadumprd >@@ -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 >-- >2.33.1 > -- Best regards, Coiby