Bug#1070150: Loading of expl3.ltx **extremely** slow on emulated runs

[Max Chernoff <mseven@telus.net>]

Hi Norbert,

On Thu, 2024-05-02 at 08:44 +0900, norbert@preining.info wrote:
> at Debian they got a report that loading expl3.ltx when building formats
> is **extremely** slow when running under emulations:
>
> 1070150 at bugs.debian.org
>
> Running fmtutil output through ts (timestamp utility from moreutils):
>
> May 01 14:28:46 LaTeX2e <2024-06-01> pre-release-0 (develop 2024-5-1 branch)
> May 01 14:28:46 (/usr/share/texlive/texmf-dist/tex/latex/l3kernel/expl3.ltx
> May 01 14:51:15 (/usr/share/texlive/texmf-dist/tex/latex/l3kernel/expl3-code.tex)) hacks,
> May 01 14:51:19 document commands, control, par, spacing, files, font encodings, lengths,
>
> That is 23 **minutes** to load expl3-code.tex. Ok, the file is nearly 4k
> lines, but still, 23 minutes seems to be excessive.

I don't think that this is TeX-related. From a Fedora 39 x86_64 host:

    $ podman run --arch arm64 --rm -it --pull always debian:stable /bin/bash

    $ apt update && \
      apt install -y moreutils && \
      apt install -y --download-only python3-minimal
    [...]

    $ time apt install -y python3-minimal | ts
    May 02 05:27:51 Reading package lists...
    May 02 05:27:52 Building dependency tree...
    May 02 05:27:52 Reading state information...
    May 02 05:27:52 The following additional packages will be installed:
    May 02 05:27:52   ca-certificates krb5-locales libexpat1 libgpm2 libgssapi-krb5-2 libk5crypto3
    May 02 05:27:52   libkeyutils1 libkrb5-3 libkrb5support0 libncursesw6 libnsl2
    May 02 05:27:52   libpython3.11-minimal libpython3.11-stdlib libreadline8 libsqlite3-0 libssl3
    May 02 05:27:52   libtirpc-common libtirpc3 media-types openssl python3.11 python3.11-minimal
    May 02 05:27:52   readline-common
    May 02 05:27:52 Suggested packages:
    May 02 05:27:52   gpm krb5-doc krb5-user python3.11-venv python3.11-doc binutils
    May 02 05:27:52   binfmt-support readline-doc
    May 02 05:27:53 The following NEW packages will be installed:
    May 02 05:27:53   ca-certificates krb5-locales libexpat1 libgpm2 libgssapi-krb5-2 libk5crypto3
    May 02 05:27:53   libkeyutils1 libkrb5-3 libkrb5support0 libncursesw6 libnsl2
    May 02 05:27:53   libpython3.11-minimal libpython3.11-stdlib libreadline8 libsqlite3-0 libssl3
    May 02 05:27:53   libtirpc-common libtirpc3 media-types openssl python3-minimal python3.11
    May 02 05:27:53   python3.11-minimal readline-common
    [...]
    May 02 05:28:40 done.

    real	0m52.253s
    user	0m51.889s
    sys	0m7.453s

    $ exit

    $ podman run --arch arm64 --rm --pull always -it debian:sid /bin/bash

    $ apt update && \
      apt install -y moreutils && \
      apt install -y --download-only python3-minimal
    [...]

    $ time apt install -y python3-minimal | ts
    May 02 05:29:22 Reading package lists...
    May 02 05:29:26 Building dependency tree...
    May 02 05:29:26 Reading state information...
    May 02 05:29:30 Installing:
    May 02 05:29:30   python3-minimal
    May 02 05:29:30
    May 02 05:29:30 Installing dependencies:
    May 02 05:29:30   ca-certificates libpython3.11-minimal media-types        readline-common
    May 02 05:29:30   libexpat1       libpython3.11-stdlib  openssl
    May 02 05:29:30   libgpm2         libreadline8t64       python3.11
    May 02 05:29:30   libncursesw6    libsqlite3-0          python3.11-minimal
    May 02 05:29:30
    May 02 05:29:30 Suggested packages:
    May 02 05:29:30   gpm python3.11-venv python3.11-doc binutils binfmt-support readline-doc
    [...]
    May 02 05:32:56 done.

    real	3m52.398s
    user	3m54.177s
    sys	0m7.514s

    $ exit

Thanks,
-- Max