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cb321 | 2 months ago

You are correct and I apologize for the misimpression.

`native-image -jar helloworld.jar helloworld` did take a whopping 17 seconds to compile, what might be the smallest possible project. That does makes me worry for iterations trying to get better perf in a context where startup overhead matters, BUT the executable it produced did run much faster - only about 1.8x slower than `tcc -run`:

    97.0 +- 1.7 μs  (AlreadySubtracted)Overhead
    98.2 +- 2.8 μs  awk '{}'</n
    376.4 +- 4.4 μs tcc -run /tmp/true.c
    527.9 +- 4.0 μs perl</n
    686.5 +- 3.9 μs ./helloworld>/n
Perl has 2 more shared libraries for ld.so to link, but is somehow faster. So, there may still be some room for improvement, but anyway, thank you for the correction.

(Also, I included 4 of the faster comparative programs to show additionally that the error bars are vaguely credible. In truth, on time shared OSes, the distributions have heavier tails than Gaussian and so a single +- is inadequate.)

--

EDIT: So, the ld.so/dynamic linking overhead was bothering me. I had to get a musl + zlib build environment going, but I did after a few minutes and then found this result with a fully statically linked binary executable:

    398.2 +- 4.2 μs ./helloworld-sta>/n
(I should have noted earlier that /n -> /dev/null is just a convenience symlink I put on all my systems. Also, this is all on Linux 6.18.2 and the same CPU as before.)

Also, only around 4.2 MiB of RSS compared to ~1.8 MiB for dash & awk. So, 2.4x the space and only ~4X the time of static awk & dash. That might sound like criticism, but those are usually the efficiency champs. The binary size is kind of hefty (~2x like the RAM use):

    $ size *sta
       text    data     bss     dec     hex filename
    2856644 3486552    3184 6346380  60d68c helloworld-sta
So, I guess, in 2026, Java start-up overhead is pretty acceptable. I hope that these "real numbers" can maybe add some precision to the discussion. Someone saying "mere milliseconds" just does not mean as much to me as 400 +- 4 microseconds, and perhaps there are others like me.

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NovaX|2 months ago

Thanks for the corrected evaluation. Just for your awareness, the HotSpot team is working on offering a spectrum of AOT/JIT options under the Leyden project [1]. Currently one has to choose between either a fully open world (JIT) or closed world (AOT) evaluation. The mixed world allows for a tunable knob, e.g. pre-warmup by AOT while retaining dynamic class loading and fast compile times for the application. This will soften the hard edges so developers can choose their constraints that best fit their application's deployment/usage model.

[1] https://openjdk.org/projects/leyden