[luatex] LuaTeX precompilation

[Hans Hagen]

On 12/20/2023 6:09 PM, Henrik Mannerström wrote:
> The following file (currently not "approved by the community”) compiles in 2.2 seconds with lualatex and in 0.3 seconds with pdflatex with a precompiled format. That is over seven times slower. When I add four pages of meaningful content (text and equations) the times are 2.5s and 0.5s, still five times slower. This is meant to be an illustration only, but not so small to be meaningless. The minimal file: \documentclass{minimal}  \begin{document} Hello World! \end{document} still takes 0.7s with lualatex.
> 
> \documentclass{article}
> 
> \usepackage{lmodern}
> \usepackage[protrusion=true,expansion=false]{microtype}
> \usepackage{geometry}
> \usepackage{mathtools}
> \usepackage{babel}
> \usepackage{csquotes}
> \usepackage{parskip}
> \usepackage{enumitem}
> \usepackage{biblatex}
> 
> \begin{document}
> Hello World!
> \end{document}
What if you replace the Hello World by \null and disable page numbers?

So,

pdftex : 0.3 sec -> 0.5 sec -> delta 0.2 sec
luatex : 2.2 sec -> 2.5 sec -> delta 0.3 sec

which means that luatex needs 0.1 sec more when we do real pages?

- 32 bit fonts with features
- unicode math
- 32 bit patterns

now, what really can slow down is protrusion and expansion (how useful 
and needed are they)? actually expansion in luatex is done a bit 
different (more granular, less font instances, etc) but I;m not sure if 
that adds much,

Hans

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