Hi Norbert,
On Thu, 2024-05-02 at 17:44 +0900, Norbert Preining wrote:
> sorry, but I don't understand!!
>
> On Wed, 01 May 2024, Max Chernoff wrote:
> > I don't think that this is TeX-related. From a Fedora 39 x86_64 host:
>
> Your data:
>
> > $ podman run --arch arm64 --rm -it --pull always debian:stable /bin/bash
> [...]
> > real 0m52.253s
>
>
> > $ podman run --arch arm64 --rm --pull always -it debian:sid /bin/bash
> [...]
> > real 3m52.398s
>
> That is a 4 times increase, ok, this does a lot of things. IN
> particular, apt uses fsync a lot.
I noticed that everything seemed much slower when trying to install the
TeX in the container, so I thought that it might be that the entire
system is slower, not just TeX.
> But what I measured in the emails is *only* the loading of one text
> file, without IO ops.
There's quite a bit of IO. From my host system:
$ sudo strace -ffe read fmtutil-sys --byfmt lualatex 2>&1 | wc -l
21440
But I've done some further testing, and my initial guess was completely
wrong (sorry). This *does* appear to be an issue particular to the
Debian TeX binaries. Using the attached file "factorial.tex" (you can
change the "10000" inside the file to "1000" if you're impatient), on my
host system I get:
$ time luatex --ini ./factorial.tex
This is LuaTeX, Version 1.17.0 (TeX Live 2023) (INITEX)
restricted system commands enabled.
(./factorial.tex)
No pages of output.
Transcript written on factorial.log.
real 0m3.952s
user 0m3.921s
sys 0m0.030s
and inside an arm64 sid container I get:
$ apt install --no-install-recommends texlive-binaries
$ wget
'https://ftp.math.utah.edu/pub/tex/historic/systems/texlive/2023/tlnet-final/archive/luatex.aarch64-linux.tar.xz'
$ tar xf luatex.aarch64-linux.tar.xz
$ cd bin/aarch64-linux
$ time luatex --ini ~/factorial.tex
This is LuaTeX, Version 1.17.0 (TeX Live 2023/Debian) (INITEX)
(/root/factorial.tex)
No pages of output.
Transcript written on factorial.log.
real 17m49.488s
user 17m49.395s
sys 0m0.016s
$ time ./luatex --ini ~/factorial.tex
warning: kpathsea: configuration file texmf.cnf not found [...]
This is LuaTeX, Version 1.17.0 (TeX Live 2023) (INITEX)
(/root/factorial.tex)
No pages of output.
Transcript written on factorial.log.
real 0m42.353s
user 0m42.319s
sys 0m0.021s
Last year, there was a similar problem where the main TeX Live LuaTeX
binaries were compiled with full debug symbols, but that was a ~50%
slowdown, not a 25x slowdown. See the thread starting at
https://tug.org/pipermail/luatex/2023-August/007853.html
or some more detailed benchmarks at
https://tug.org/pipermail/luatex/2023-August/007875.html
https://tug.org/pipermail/luatex/2023-August/007864.html
Looking through the build logs
https://tests.reproducible-builds.org/debian/rbuild/unstable/amd64/texlive-bin_2023.20230311.66589-9.rbuild.log.gz
it looks like the LuaTeX binaries were compiled with "-g -O2", but
running "readelf" and "objdump" shows that they're stripped, so I don't
think that that's the issue here.
And this issue appears to affect all engines: I also tried testing with
pdfTeX (comment out the \directlua line, and add the --etex command line
flag), and for 1000 iterations I got:
Debian Sid arm64 LuaTeX: 0m15.392s
Debian Sid arm64 pdfTeX: 0m7.914s
TeX Live 2023 arm64 LuaTeX: 0m0.737s
TeX Live 2023 x86_64 pdfTeX: 0m0.156s
TeX Live 2023 x86_64 LuaTeX: 0m0.156s
I'm not sure what's going on here, but hopefully this gives you some
clues.
Thanks,
-- Max
\catcode`\{=1
\catcode`\}=2
\catcode`\#=6
\directlua{tex.enableprimitives("", tex.extraprimitives("etex"))}
\def\factorial#1{%
\ifnum#1=0
1%
\else%
\numexpr\factorial{\numexpr#1 - 1\relax} * #1\relax%
\fi%
}
\def\loop#1\repeat{\def\body{#1}\iterate}
\def\iterate{\body \let\next=\iterate \else\let\next=\relax\fi \next}
\let\repeat=\fi
\def\out{}
\countdef\n=0
\loop\ifnum\n<10000
\edef\out{\out \the\factorial{12}}
\advance\n by 1
\repeat
\end
