On Sat, Sep 11, 2021 at 06:25:34AM -0700, John Reiser wrote: > >FWIW, I've been playing with zstd-coompressed initrd images. > >With a large initd image, it shaves about 1 second from the boot > >time. > Please give numeric statistics. How many MB is large, > and how many seconds does it take?
$ time xzcat initrd-5.14.1-300.fc35.x86_64.cpio.xz >/dev/null 3.32s user 0.03s system 99% cpu 3.371 total $ time zstdcat initrd-5.14.1-300.fc35.x86_64.cpio.zstd >/dev/null 0.21s user 0.02s system 69% cpu 0.323 total $ ls -lh initrd-5.14.1-300.fc35.x86_64.cpio* 135M initrd-5.14.1-300.fc35.x86_64.cpio 51M initrd-5.14.1-300.fc35.x86_64.cpio.xz 58M initrd-5.14.1-300.fc35.x86_64.cpio.zstd The time is obviously proportional to the initrd size. With a host-specific dracut initrd with no frills, the image is about 40MB compressed and the uncompression time is less than one second with xz. The *ratio* is similar, but one second during early boot is less visible. (This is in userspace. But the implementation in the kernel is sharing the same code, so the results should be similar. The in-kernel code for zstd is currently lacking some speed improvements that were introduced in zstd-1.5.0, but people are working on an update there too.) Zbyszek _______________________________________________ devel mailing list -- devel@lists.fedoraproject.org To unsubscribe send an email to devel-le...@lists.fedoraproject.org Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org Do not reply to spam on the list, report it: https://pagure.io/fedora-infrastructure
