Initrd compression with zstd -19 takes ages

[ArjenR]

How did you upgrade to 21.10? (Fresh install / Upgrade)

Upgrade from 21.04

Related Application and/or Package Version (run apt policy $PACKAGE NAME):

zstd: Installed: 1.4.8+dfsg-2.1 Candidate: 1.4.8+dfsg-2.1 Version table: *** 1.4.8+dfsg-2.1 500 500 http://us.archive.ubuntu.com/ubuntu impish/main amd64 Packages 100 /var/lib/dpkg/status

initramfs-tools: Installed: 0.140ubuntu6 Candidate: 0.140ubuntu6 Version table: *** 0.140ubuntu6 500 500 http://us.archive.ubuntu.com/ubuntu impish/main amd64 Packages 500 http://us.archive.ubuntu.com/ubuntu impish/main i386 Packages 100 /var/lib/dpkg/status

Issue/Bug Description: updates involving a new kernel or updated dkms modules like the system76 power package take a long time due to slow initial ramdisk compression. Compression level 19 is used.

Steps to reproduce (if you know): Update and or upgrade the system.

Expected behavior: As fast as 21.04

Other Notes: Perhaps initramfs-tools is expecting zstd version 1.5 (or later) which is reported to have significant speed improvements.

[jacobgkau]

Can you please give a number of seconds (or minutes) that "a long time" refers to? It is normal for this to take longer than most of the other steps when updating packages.

[celestialorb]

I'm experiencing this issue as well, any kind of package install that involves touching initramfs will take minutes to run zstd.

[yaxu]

Just had my laptop turn on its fans and saw a weird 'zstd' process using 400% cpu.. Almost killed it then but looked in pstree first and saw it was something to do with the kernel and decided I should let it run.