I like smaller install size. In many cases we boot without initrd by default (gcp, azure, aws, kvm). Does it then make sense to enable this for the cloud kernels?
I ponder, if i can hack initramfs-tools to append compressed kernel modules as an uncompressed cpio archive to the initramfs, instead of having it together with the userspace bits all compressed together. Separately, are the modules signed, then compressed, or compressed then signed? Cause the other alternative is to decompress the modules whilst including in the initramfs. That way we should get unchanged initrd sizes. So I guess I need to hack initramfs-tools more. -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1932329 Title: Benchmark if we can compress kernel modules Status in linux package in Ubuntu: In Progress Bug description: Symbol: MODULE_COMPRESS_ZSTD [=n] Type : bool = Impacts to measure and observe = == Disk space == * Inspect linux-modules-* and linux-modules-extra* deb package Installed-Size and Download-Size changes, i.e. $ apt show linux-modules-5.8.0-53-generic linux-modules- extra-5.8.0-53-generic | grep -e Package: -e Size: Package: linux-modules-5.8.0-53-generic Installed-Size: 81.5 MB Download-Size: 15.5 MB Package: linux-modules-extra-5.8.0-53-generic Installed-Size: 215 MB Download-Size: 41.5 MB In theory, there should not be a significant change in the Download- size. It is desired that there is a significant reduction in Installed-Size. Modules take up about 300MB and normally one has upto three kernel version installed, resulting in about of 1GB of disk space that one constantly pays for. == Boot Speed == In theory, boot speed may either improve or regress. It depends if disk IO is slower than decompression speed, meaning loading compressed modules is faster. Also one has to observe the changes in the initrd size. zstd(zstd) compression may result in slight growth, which shouldn't impact boot speed too much. = Outcomes = If installed size savings can be achieved without regressing bootspeed we should enable CONFIG_MODULE_COMPRESS_ZSTD=y by default. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1932329/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
