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

[Paulo Roberto Massa Cereda]

Grazie, Luigi! Will investigate further. :)

Em seg., 28 de ago. de 2023 às 13:34, luigi scarso
<luigi.scarso at gmail.com> escreveu:

>
>
>
> On Mon, 28 Aug 2023 at 16:50, Paulo Roberto Massa Cereda <cereda.paulo at gmail.com> wrote:
>>
>> Dear friends,
>>
>> I beseech your wisdom. :) In my tests, I noticed LuaTeX 2023 is
>> significantly slower than the 2022 counterpart. Here's a MWE:
>>
>> --------8<--------
>> Lorem ipsum dolor sit amet, consectetur adipiscing elit,
>> sed do eiusmod tempor incididunt ut labore et dolore magna
>> aliqua. Ut enim ad minim veniam, quis nostrud exercitation
>> ullamco laboris nisi ut aliquip ex ea commodo consequat.
>> Duis aute irure dolor in reprehenderit in voluptate velit
>> esse cillum dolore eu fugiat nulla pariatur. Excepteur
>> sint occaecat cupidatat non proident, sunt in culpa qui
>> officia deserunt mollit anim id est laborum.
>> \bye
>> --------8<--------
>>
>> Benchmark 1: texlive/2022/bin/x86_64-linux/luatex test.tex
>>   Time (mean ± σ):     177.7 ms ±   1.4 ms    [User: 140.9 ms, System: 36.6 ms]
>>   Range (min … max):   175.8 ms … 180.3 ms    16 runs
>>
>> Benchmark 2: texlive/2023/bin/x86_64-linux/luatex test.tex
>>   Time (mean ± σ):     286.7 ms ±   2.3 ms    [User: 246.1 ms, System: 40.3 ms]
>>   Range (min … max):   284.0 ms … 291.2 ms    10 runs
>>
>> Summary
>>   texlive/2022/bin/x86_64-linux/luatex test.tex ran
>>     1.61 ± 0.02 times faster than texlive/2023/bin/x86_64-linux/luatex test.tex
>>
>> I initially had tried with LuaLaTeX and got similar results. Ulrike
>> Fischer and Marcel Krüger kindly helped me find out what was going on,
>> but we could not find anything relevant. I've tried:
>>
>> - loading a custom OTF font: 2022 was 1.53 ± 0.02 (cold cache) and
>> 1.83 ± 0.03 (existing cache) times faster
>> - loading the default OTF font: 2022 was 1.68 ± 0.02 (cold cache) and
>> 2.02 ± 0.03 (existing cache) times faster
>> - HarfBuzz: 2022 was 1.57 ± 0.02 times faster (cold cache) and 1.84 ±
>> 0.05 times faster (existing cache)
>> - raw feature (normalize): 2022 was 1.81 ± 0.03 times faster
>> - updated luaotfload-tool in TL2022: 2022 was 1.83 ± 0.01 times faster
>> - no OTF: 2022 was 1.95 ± 0.02 times faster
>>
>> I was wondering if someone could shed some light into this. :) Thanks!
>>
>
>
> I have done some quick tests (running luatex test.tex) and the wall clock here is roughly 0.30s  in both cases
> (luatex 2022 seems to be more near to 0.29 than 0.30).
> Intel(R) Core(TM) i7-7500U CPU @ 2.70GHz, 24GB , HDD 5400rpm
>
> --
> luigi
>