-------- Forwarded Message -------- Subject: Re: bug#62069: Support xz parallel compression in dist-xz Date: Sun, 30 Aug 2026 09:14:18 +0200 From: Kamila Szewczyk <[email protected]> To: Collin Funk <[email protected]>, Karl Berry <[email protected]> CC: [email protected], [email protected], [email protected] I agree with everything as stated previously. I will close the ticket now. Thanks for the discussion. -- With Valediction, Kamila Szewczyk (https://iczelia.net) On 8/29/26 10:46 PM, Collin Funk wrote: > Karl Berry <[email protected]> writes: > >> Regarding https://debbugs.gnu.org/cgi/bugreport.cgi?bug=62069. >> >> Given Kamila's point about reproducibility, and the xz version >> dependence of the feature, I don't think we should change automake's >> default of unthreaded. > > I can't speak to Kamila's point about reputability or stability since it > isn't my area of expertise, but I think that just invoking the command > with none (or minimal) options is a reasonable choice. Package > maintainers can make their own decisions on whether they want new > compression features or maximize portability, for example. > >> Thus I think the only change called for here is to update the doc to >> mention that -T0 (or another value) can presumably be added to XZ_OPT if >> a maintainer wishes to make thread-dependent, and xz-version-dependent, >> tarballs. > > Yes, it works fine. In coreutils we have the following in cfg.mk: > > # Comparing tarball sizes compressed using different xz presets, we see > that > # an -8e-compressed tarball is only 9KiB larger than the -9e-compressed > one. > # Using -8e is preferred, since that lets the decompression process use > half > # the memory (32MiB rather than 64MiB). > # $ for i in {7,8,9}{e,}; do \ > # (n=$(xz -$i < coreutils-8.15*.tar|wc -c);echo $n $i) & done |sort > -nr > # 5129388 7 > # 5036524 7e > # 5017476 8 > # 5010604 9 > # 4923016 8e > # 4914152 9e > export XZ_OPT = -8e > > Many of the packages Jim Meyering maintains have similar lines (I'm sort > of surprised he didn't add it to 'make dist' for Automake's tarballs). > > FWIW, we haven't run into any complaints about the xz formatted tarballs > in coreutils because of this. They seemingly work fine everywhere. There > was a minor exception where GNU Guix wanted gzip'ed tarballs for > bootstrapping, but I think they haven't needed that for a while now. > > Collin > > >
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