Re: Compressing compressed files

[ludo@gnu.org (Ludovic Courtès)]

Hi!

Andreas Enge <andreas@enge.fr> skribis:

> I am seeing this funny command being executed on one of the build machines:
>    bash -c guix archive --export /gnu/store/06g54r7am7ka96d7jydgmayfyqgx1s1l-cfe-3.5.2.src.tar.xz | xz -c
>
> Would it be difficult to prevent re-compressing of already compressed
> source when offloading? Especially since xz is rather expensive, and more
> or less occupies one core of the arm machines.

This all takes place in (guix scripts offload) and should be relatively
easy to modify (see commit 5ef9d7deeab348e0f714f91a3c02ce4b72bbe3c1 for
an example).

[Time passes…]

I thought it would be quicker to fix it but was proved wrong, because
‘guix substitute’ expects to be able to pass non-file ports to
‘decompressed-ports’, which means we cannot just use ‘duplicate-port’
there.  Anyway, I’ve pushed ‘wip-offload-compression’ and we’ll look at
it again after the release.

Thanks,
Ludo’.