Re: Reminder: Review for Zach's parsing library starts on Feb 19th

From: Christian Mazakas (christian.mazakas_at_[hidden])
Date: 2024-02-29 23:14:15

> It is up to you. I think Zach would appreciate knowing if there was a
> significant performance issue with the library.

Fwiw, there is a dramatic performance penalty to using this library and I
almost
couldn't believe it.

I copy-pasted the JSON example from the Parser repo and then did an
informal comparison
to Boost.JSON.

For one, Boost.JSON should just export a proper CMake target like all the
other compiled Boost
libraries.

And then two, these were my findings:
    ❯ ./__build__/test/json_bench
/home/exbigboss/cpp/boost-root/libs/json/bench/data/twitter.json
    Boost.Parser
    took: 1037ms
    parse successful!  1
    Boost.JSON
    took: 1ms
    parse successful!  1

Source: https://github.com/cmazakas/parser-review/blob/main/test/json.cpp

I'm running all of this on a 3.6 GHz 12 core with 32 GB of RAM. I'm
honestly shocked that
it takes Boost.JSON roughly 1ms whereas it takes roughly 1000x that with
Parser.

I will note this, I did have to increase the recursion limit so I'm
thinking this is actually more or
less a fault in the implementation of the recursive parsing rules in
Parser. Either way, this is 112%
worth investigating and I'd almost recommend halting acceptance until we
sort this out.

- Christian