https://bugzilla.suse.com/show_bug.cgi?id=1192457 https://bugzilla.suse.com/show_bug.cgi?id=1192457#c39 --- Comment #39 from Martin Wilck <martin.wilck@suse.com> --- Quick test on 5.14.14, x86_64: The last column is the size of the modules tree after the command in the first column. The other columns indicate times and max RSS. 446MiB is the uncompressed size. All tests run consecutively, i.e. from the page cache. command real sys usr mem size "xz" 143 "xz -d" 0:07.58 0.56 7.01 4268 446 "xz -0" 0:20.15 0.49 19.65 4880 151 "xz -d" 0:08.05 0.55 7.49 2424 446 "zstd -21 --rm -q -T0" 2:21.79 0.95 140.75 114156 153 "zstd -d --rm -q" 0:01.71 0.60 0.89 11216 447 "zstd -15 --rm -q -T0" 0:49.35 0.77 48.53 96104 158 "zstd -d --rm -q" 0:01.33 0.65 0.67 7488 447 "zstd -10 --rm -q -T0" 0:11.17 0.54 10.59 40760 162 "zstd -d --rm -q" 0:01.24 0.54 0.66 7436 447 "zstd -6 --rm -q -T0" 0:05.79 0.53 5.30 32388 166 "zstd -d --rm -q" 0:01.28 0.49 0.77 5336 447 "zstd -3 --rm -q -T0" 0:03.06 0.51 2.56 25324 171 "zstd -d --rm -q" 0:01.88 0.79 1.04 5460 447 "zstd -0 --rm -q -T0" 0:03.24 0.58 2.69 25404 171 "zstd -d --rm -q" 0:01.24 0.52 0.71 5460 447 xz -6 (standard level) compression takes about 2:20 minutes. You can see that decompression time is actually constantly low with zstd. zstd -10 wins about 9MB, or 6% relative to the default size, compared to zstd -3, taking 4x as much time. Given that the compression time matters only during kernel building, and "zstd -10" is still 14x faster than "xz -6", it might be a good compromise. We could actually go for "zstd -21 -T0": The compression time is about the same as xz -6, and we'd loose just ~6% disk space. -- You are receiving this mail because: You are the assignee for the bug.