[luatex] Performace comparison

[Hans Hagen]

On 11/30/2023 7:32 PM, Andreas Scherer wrote:
> Dear all,
> 
> While working on next year's 'knuth-pdf' package 
> (https://ctan.org/pkg/knuth-pdf) I have noticed that LuaTeX is the one 
> PDF engine that revs up the fan of my laptop more than the others.
> 
> Running 'time makeall' (see 
> https://mirrors.ctan.org/web/pwebmac/makeall) gives the following 
> results (second run each):
> 
> $ time makeall -npt xetex
> real    1m2,738s
> user    1m7,745s
> sys     0m8,641s
> [$ wc -c *.pdf -> 30355436 total]
> 
> $ time makeall -npt pdftex
> real    0m53,242s
> user    0m53,042s
> sys     0m2,140s
> [$ wc -c *.pdf -> 40045111 total]
> 
> $ time makeall -npt luatex
> real    1m15,286s
> user    1m13,728s
> sys     0m3,615s
> [$ wc -c *.pdf -> 44176632 total]
> 
> Just an observation.
So (just a remark),

pdftex  53 sec  8 bit input, 8 bit fonts
xetex   63 sec  utf input, wide fonts
luatex  75 sec  utf input, wide fonts

Given the 53 sec which is quite some for a pdftex run, luatex is not 
doing that bad. On pure text runs luatex with open type fonts can be 
three times slower, and depending on circumstances xetex can be faster 
than luatex (so that metric looks ok compared to the others).

Of course there are scenarios where luatex can be faster. Anyway, 
unicode and wide fonts have impact on the parsing of input, memmory 
usage, font handling, language processing, backend etc.

Hans

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