The Linux kernel is now supplying modules compressed with zstd. Version updates for 5.12 and 5.13 are unable to be installed anymore on Debian due to this issue being unresolved.
Thanks, Sam Johnston On Sun, 10 Jan 2021 19:19:05 +0100 Balint Reczey < balint.rec...@canonical.com> wrote: > Hi Sebastian, > > On Sun, Apr 12, 2020 at 1:09 AM Sebastian Andrzej Siewior > <sebast...@breakpoint.cc> wrote: > > > > On 2018-03-11 21:51:05 [+0100], Balint Reczey wrote: > > > For the recompressed firefox .deb (Ubuntu's > > > firefox_58.0.2+build1-0ubuntu0.17.10.1_amd64.deb) increased ~9% in > > > size but decompressed in <20% of the original time: > > > > So you are saying that the decompression speed that is the bottleneck > > here? I *assumed* that it is mostly the disk speed since I get around 60 > > to 80MiB/sec out of xz. > > I would not say bottleneck, but a very big contributor to the CPU time > used. Some systems can have very slow IO and very fast CPU, but I > think those typically correlate positively and SSDs are more common > than spinning disks improving the typical IO speed. > > > > $ du -s firefox-*deb > > > 43960 firefox-xz.deb > > > 47924 firefox-zstd.deb > > > > 48M linux-image-5.5.0-1-amd64_5.5.13-2_amd64.data.tar.xz > > 54M linux-image-5.5.0-1-amd64_5.5.13-2_amd64.data.tar.19.zstd > > > > 766M linux-image-5.5.0-1-amd64-dbg_5.5.13-2_amd64.data.tar.xz > > 901M linux-image-5.5.0-1-amd64-dbg_5.5.13-2_amd64.data.tar.19.zstd > > > > zstd -19 -T16 > > |linux-image-5.5.0-1-amd64-dbg_5.5.13-2_amd64.data.tar : Completed in 287.37 sec (cpu load : 1533%) > > | > > |real 4m47,416s > > |user 73m23,825s > > |sys 0m2,753s > > | > > > > xz -T16 > > | real 4m15,447s > > | user 66m51,572s > > | sys 0m3,201s > > > > > > > $ rm -rf firefox-xz/* ;time dpkg-deb -R firefox-xz.deb firefox-xz/ > > > real 0m4,270s > > > user 0m4,220s > > > sys 0m0,630s > > > $ rm -rf firefox-zstd/* ;time dpkg-deb -R firefox-zstd.deb firefox-zstd/ > > > real 0m0,765s > > > user 0m0,556s > > > sys 0m0,462s > > > > So this looks impressive. Is dpkg-deb also performing sync() on the > > output or is the report when the files hit the disk cache? Either way, > > should be noticeable on ssd/nvme which write at higher performance. > > > > > Tests on the full Ubuntu main archive showed ~6% average increase in > > > the size of the binary packages. > > > > I guess the vast majority of packages are small and hardly increase in
