On Wed, 9 Mar 2022, Julian Andres Klode wrote: > On Wed, Mar 09, 2022 at 02:10:57PM +1300, Michael Hudson-Doyle wrote: > > On Thu, 9 Dec 2021 at 06:13, Julian Andres Klode > > <julian.kl...@canonical.com> > > wrote: > > > changed from lz4 -9 to zstd -19. This caused significant problems: > > change to initramfs-tools to allow the compression level to be configured > xypron had a patch to change the default level to 9 ... > think the summary from the Frankfurt discussion was: ...
I live in Frankfurt, but wasn't there...; otherwise some observations could have been made: Choosing the best (size) of hammer, to nail in a screw, is un-useful. Using four screwdrivers with four small screws seems quick; but only if four screws are an acceptable engineering solution. [Pigz chops the stream into independent (128 kB) blocks and round-robins these per CPU/thread + concats() afterwards]. When the output is made of independent concatentated chunks; each chunk *may* have its own compression level; ...chosen from reasonable heuristics [file size + content type (+ available local resources)]. With the same input stream, && the same heuristics, this will always generate the same (identical) outputs. Which means the (previous) outputs can be cached and (re-)used, or ...precalculated in the background. Which means initramfs generation *could* be turned into a ~1 second "cat *.cpio.gz > initramfs.cpio.gz" operation. -Paul -- ubuntu-devel mailing list ubuntu-devel@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-devel