> I have implemented the listing of uncompressed cpio archives (roughly 120 lines of code). Now I have to add the decompression support
Finding offsets of the embedded archives is the only time consuming part of the whole script. Mby it is better to create a separate tool, say "scaninitramfs", to only list offsets and size of embedded archives, just like my tools' "-s" option does, and use it in the original script? Scan output can be of interest beyond unmkinitramfs. For example, if you need to know the compression used in some initrd. With a scan tool you can quickly get the offset of the compressed cpio and "dd .. | file .." -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to initramfs-tools in Ubuntu. https://bugs.launchpad.net/bugs/2059976 Title: unmkinitramfs is very slow on initrd from ubuntu 23.10+, solution proposed Status in initramfs-tools package in Ubuntu: New Bug description: Since 23.10 the initrd consists of 4 embedded cpio: - amd microcode - intel microcode - firmware + kernel modules - rest (compressed) Previously it was: - amd microcode - intel microcode - rest (compressed) There is no archive size header for cpio, so unmkinitramfs has to parse headers of each entry in uncompressed archives. > time unmkinitramfs 23.04/{initrd,unpack} real 0m3.625s user 0m1.595s sys 0m3.467s > time unmkinitramfs 23.10/{initrd,unpack} real 0m15.982s user 0m20.174s sys 0m6.995s > for dir in 23.04/unpack/early*; do printf '%-20s %s\n' "$dir" "$(find "$dir" | wc -l)"; done 23.04/unpack/early 5 23.04/unpack/early2 6 > for dir in 23.10/unpack/early*; do printf '%-20s %s\n' "$dir" "$(find "$dir" | wc -l)"; done 23.10/unpack/early 5 23.10/unpack/early2 6 23.10/unpack/early3 2874 Here https://github.com/slowpeek/unmkinitramfs-turbo I've made it a lot faster with two changes: - bash instead of sh for bash's "read -N" - xxd dump of initrd instead of raw binary data I wonder, if the developers are interested in accepting my improvements into the code base? > time unmkinitramfs-classic-turbo 23.10/{initrd,unpack} real 0m2.209s user 0m2.161s sys 0m1.341s > time unmkinitramfs-turbo 23.10/{initrd,unpack} early .. + early2 .. + early3 .. + main .. + real 0m1.973s user 0m2.094s sys 0m1.244s All tools in the repo, even the classic one, feature -s/--scan option. With it, the tools only dump offset + size for embedded archives, nothing is unpacked. It can be used to measure parsing speed. In the repo there are three tools: - unmkinitramfs-classic: the original tool - unmkinitramfs-classic-turbo: the improved tool with minimal changes - unmkinitramfs-turbo: the improved tool with many changes to my tastes, extra dependency on "file" and some additional features (-ss option, decompression with 7za) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/initramfs-tools/+bug/2059976/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
