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Re: zstd compression for packages


On Mon, Mar 12, 2018 at 11:06:11AM +0100, Julian Andres Klode wrote:
> Hey folks,
> 
> We had a coding day in Foundations last week and Balint and Julian added support for zstd compression to dpkg [1] and apt [2].
> 
> [1] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=892664
> [2] https://salsa.debian.org/apt-team/apt/merge_requests/8
> 
> Zstd is a compression algorithm developed by Facebook that offers far 
> higher decompression speeds than xz or even gzip (at roughly constant 
> speed and memory usage across all levels), while offering 19 compression 
> levels ranging from roughly comparable to gzip in size (but much faster) 
> to 19, which is roughly comparable to xz -6:
> 
> In our configuration, we run zstd at level 19. For bionic main amd64, 
> this causes a size increase of about 6%, from roughly 5.6 to 5.9 GB. 
> Installs speed up by about 10%, or, if eatmydata is involved, by up to 
> 40% - user time generally by about 50%.
> 
> Our implementations for apt and dpkg support multiple frames as used by 
> pzstd, so packages can be compressed and decompressed in parallel 
> eventually.

More links:

PPA:               https://launchpad.net/~canonical-foundations/+archive/ubuntu/zstd-archive
APT merge request: https://salsa.debian.org/apt-team/apt/merge_requests/8
dpkg patches:      https://bugs.debian.org/892664

I'd also like to talk a bit more about libzstd itself: The package is
currently in universe, but btrfs recently gained support for zstd,
so we already have a copy in the kernel and we need to MIR it anyway
for btrfs-progs.

-- 
debian developer - deb.li/jak | jak-linux.org - free software dev
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