[luatex] Identifying why LuaTeX 2023 is slower than LuaTeX 2022

[Hans Hagen]

On 8/28/2023 5:43 PM, Paulo Roberto Massa Cereda wrote:
> Thanks for the feedback, Hans! Apologies for the "vague" context, I
> was in a hurry. I will try to provide more details as follows:
> 
> My initial test was:
> 
> --------8<--------
> \documentclass{article}
> 
> \usepackage{fontspec}
> 
> \setmainfont[
>      Extension=.ttf,
>      Path=./fonts/,
>      UprightFont=*-Regular,
>      BoldFont=*-Bold,
>      ItalicFont=*-Italic,
>      BoldItalicFont=*-BoldItalic
> ]{JetBrainsMono}
> 
> \begin{document}
> 
> Hello world.
> 
> \end{document}

So that is mostly measuring start up time.

There is no real big difference between jetbrain regular and for 
instance dejavu sans mono):

1000 lorum paragraphs (standard 12pt context layout):

% jetbrain : 200 pages 1.4 sec
% dejavu   : 200 pages 1.2 sec

if we just process the font (hbox)

% jetbrain : 0.39 sec (0.15) sec for 200 pages
% dejavu   : 0.36 sec (0.15) sec for 200 pages

in base mode:

% jetbrain : 0.15 sec for 200 pages
% dejavu   : 0.15 sec for 200 pages

(windows 10, luametatex with context, 2017 laptop with Intel(R) Xeon(R) 
CPU E3-1505M v6 @ 3.00GHz)

Just to give you some comparison.

> --------8<--------
> 
> JetBrains Mono was obtained from here: https://www.jetbrains.com/lp/mono/
> 
> By "cold cache" (and apologies in advance for probably using the wrong
> term for describing), I was referring to deleting
> 
> texmf-var/luatex-cache
> 
> before each benchmark run. I did this with both TL 2022 and TL 2023.
> 
> Then I tried with an actual document. I had Lorem Ipsum paragraphs
> replicated more than 1000 times:
> 
> ➜ wc -l test.tex
> 2499 test.tex
> 
> ➜ hyperfine -L year 2022,2023 --warmup 2
> 'texlive/{year}/bin/x86_64-linux/lualatex test.tex'
> Benchmark 1: texlive/2022/bin/x86_64-linux/lualatex test.tex
>    Time (mean ± σ):      2.881 s ±  0.021 s    [User: 2.771 s, System: 0.108 s]
>    Range (min … max):    2.848 s …  2.907 s    10 runs
> 
> Benchmark 2: texlive/2023/bin/x86_64-linux/lualatex test.tex
>    Time (mean ± σ):      5.814 s ±  0.059 s    [User: 5.675 s, System: 0.128 s]
>    Range (min … max):    5.760 s …  5.910 s    10 runs

hm, so startup time differences can be neglected

> Summary
>    texlive/2022/bin/x86_64-linux/lualatex test.tex ran
>      2.02 ± 0.03 times faster than
> texlive/2023/bin/x86_64-linux/lualatex test.tex
> 
>   For HarfBuzz, I had the OTF font example above with:

That could be changes in that library, right?

> \setmainfont[
>      Extension=.ttf,
>      Path=./fonts/,
>      UprightFont=*-Regular,
>      BoldFont=*-Bold,
>      ItalicFont=*-Italic,
>      BoldItalicFont=*-BoldItalic,
>      Renderer=HarfBuzz
> ]{JetBrainsMono}
> 
> For the normalize thing one, I had:
> 
> \setmainfont[
>      Extension=.ttf,
>      Path=./fonts/,
>      UprightFont=*-Regular,
>      BoldFont=*-Bold,
>      ItalicFont=*-Italic,
>      BoldItalicFont=*-BoldItalic,
>      RawFeature=-normalize
> ]{JetBrainsMono}
> 
> Marcel suggested me to update TL2022 luaotfload-tool to the latest
> version as well, so I did:
> 
> ➜ texlive/2022/bin/x86_64-linux/luaotfload-tool --version | grep
> "luaotfload-tool version"
> luaotfload-tool version: "3.24"
> 
> ➜ texlive/2023/bin/x86_64-linux/luaotfload-tool --version | grep
> "luaotfload-tool version"
> luaotfload-tool version: "3.24"
> 
> ➜ hyperfine -L year 2022,2023 --warmup 2
> 'texlive/{year}/bin/x86_64-linux/lualatex test.tex'
> Benchmark 1: texlive/2022/bin/x86_64-linux/lualatex test.tex
>    Time (mean ± σ):     689.6 ms ±   2.0 ms    [User: 588.9 ms, System: 100.1 ms]
>    Range (min … max):   687.3 ms … 693.6 ms    10 runs
> 
> Benchmark 2: texlive/2023/bin/x86_64-linux/lualatex test.tex
>    Time (mean ± σ):      1.264 s ±  0.007 s    [User: 1.151 s, System: 0.112 s]
>    Range (min … max):    1.254 s …  1.277 s    10 runs
> 
> Summary
>    texlive/2022/bin/x86_64-linux/lualatex test.tex ran
>      1.83 ± 0.01 times faster than
> texlive/2023/bin/x86_64-linux/lualatex test.tex
> 
> I also tried with \usepackage[T1]{fontenc}:
> 
> ➜ hyperfine -L year 2022,2023 --warmup 2
> 'texlive/{year}/bin/x86_64-linux/lualatex test.tex'
> Benchmark 1: texlive/2022/bin/x86_64-linux/lualatex test.tex
>    Time (mean ± σ):     457.4 ms ±   3.1 ms    [User: 380.7 ms, System: 76.3 ms]
>    Range (min … max):   452.8 ms … 463.6 ms    10 runs
> 
> Benchmark 2: texlive/2023/bin/x86_64-linux/lualatex test.tex
>    Time (mean ± σ):     893.9 ms ±   8.4 ms    [User: 805.5 ms, System: 88.0 ms]
>    Range (min … max):   886.8 ms … 915.7 ms    10 runs
> 
> Summary
>    texlive/2022/bin/x86_64-linux/lualatex test.tex ran
>      1.95 ± 0.02 times faster than
> texlive/2023/bin/x86_64-linux/lualatex test.tex
> 
> I can create a GitHub repository with some tests for reproducibilty,
> if it helps.
> 
> I will try to compile the sources. Will report soon.
best try that first because it might be that you have a subtoptimal 
binary or get bins from

https://dl.contextgarden.net/build/luatex/

(these are generated in the tex live setup so basically for older 
linuxes in order to be compatible)

Hans

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                                           Hans Hagen | PRAGMA ADE
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