Thank you very much for testing.

I didn't use such tools. I am watching the terminal when fonts are downloaded (at the end of the document) and I notice the delay per each Besley fonts downloaded from ~/texmf. Sure, it is observable. It looks like waiting for some kind of time limit.

Unfortunately, questions remains: why behavior of Lua garbage collector differs in luatex and luahbtex when the programs have to do the same?

When we copy the fonts from ~/texmf/fonts to current directory:

   cp ~/texmf/fonts/opentype/besley/* .

and run the test, then the unwanted delay with luahbtex disappears. It seems that this has something to do with file searching from TeXmf tree. Garbage collector behavior differs when files are in in different locations?

Best regards

Petr Olsak

On Sun, 19 Jan 2025 at 19:32, luigi scarso <luigi.scarso@gmail.com> wrote:

On Sun, 19 Jan 2025 at 11:37, Petr Olsak <petr@olsak.net> wrote:

Hello

I am testing new luahbtex and comparing it with luatex because I am
considering to set OpTeX with luahbtex engine instead luatex in TeXlive
2025.
I have found a difference between lautex and luahbtex behavior which I
am unable to explain why. The difference is shown only when huge number of
fonts are downloaded by luaotfload and only with selected fonts from
internet saved to ~/texmf/fonts. And it manifests only as a little delay
(with luahbtex) during dlownloading the fonts to PDF at the end of the
document visible if you are watching at the terminal. The PDF result is
equal, but I am worried that there is a hidden bug in luahbtex because
the difference is unexpected.

I teseted this with OpTeX macros, they never use mode=harf. So I expect the
same behavior with both engines. The example for testing is somewhat more
complicated and it is exactly described at

    https://tex.stackexchange.com/questions/735071/

The main question is: why luatex behaves correctly (with no delay during
downolading fonts) but luahbtex presents a delay in given cases? Where is
the difference? Can the luatex developers explain this?

Thank you

Petr Olsak

under linux

/usr/bin/time always reports  luahbtex slower of about 5seconds,

but  I was not able to find why /where. 

--

luigi

 

Using gprofng

 https://sourceware.org/binutils/wiki/gprofng

I can see that luahbtex spends a relevant time on sweeplist, which means that the lua gc  plays an important  role here.

--

luigi