[luatex] LuaTeX precompilation

[Hans Hagen]

On 12/21/2023 10:01 AM, Henrik Mannerström wrote:
> On Thu, Dec 21, 2023 at 10:40 AM luigi scarso <luigi.scarso at gmail.com 
> <mailto:luigi.scarso at gmail.com>> wrote:
> 
>     I think we should  start from
>     https://tex.stackexchange.com/questions/324559/guidelines-for-using-mylatexformat-with-luatex <https://tex.stackexchange.com/questions/324559/guidelines-for-using-mylatexformat-with-luatex>
> 
> True! The goal behind my question was a bit more ambitious: Do dump 
> (serialise) the whole state of the luatex engine into a restartable 
> glob. Or even better, to have a tex-server that never leaves memory. 
> This way I can do my type-recompile loop without interrupting by flow.

On modern machines and os's tex actually never leaves memory; the binary 
and format are likely cached. Just compare two times making a format 
after a machine startup.

As a service one would have to reset some states ... which ones? How to 
reset bits of lua without restarting it?

>     (precompiled format it's a bit misleading --  a format it's already
>     a  set of compiled macros. I prefer custom format, as the link says)
> 
> It does not have to be a custom format in a strict TeX-sense, in that it 
> is saved somewhere permanently. I usually work on only one document at a 
> time, so I'm totally happy with one lengthy setup and then fast iterations.

You can only partially save the state of lua. In tex there's also the 
backend to keep in mind which has its own states. And here's the 
multiple run issue. It gets really complex.

What you could try to do is start N tex instances and let them sit idle 
till triggered and onece doen start it again, but then teh controller 
program needs to know which ons is ready.

What does has some impact is large cpu caches, fast memory (here ddr4 
can beat ddr5), not having some zoom session (trying to improve a fuzzy 
real time image) or 25 browser tabs open (taking gig's of mem) with a 
music app running in the background.

Hans

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