Re: New JSON library from the maker of Beast!

From: Vinnie Falco (vinnie.falco_at_[hidden])
Date: 2019-10-22 22:40:42

On Tue, Oct 22, 2019 at 3:13 PM Daniel Frey via Boost
<boost_at_[hidden]> wrote:
> That sounds like you should stop using the STL altogether. What if std::string is suddenly 2x slower? So... no, I don't buy that argument.
>
> I just switched our JSON library <https://github.com/taocpp/json> from
> our own classic enum+union implementation (back from the C++11 days)
> over to std::variant (as we are now C++17 anyways).

Any idea why taocpp compiled with optimizations is 5 to 10 times
slower than the other libraries at parsing the same inputs?

Boost.JSON parse 55952763 bytes in 234ms
Boost.JSON parse 55952763 bytes in 232ms
Boost.JSON parse 55952763 bytes in 231ms
rapidjson parse 55952763 bytes in 239ms
rapidjson parse 55952763 bytes in 240ms
rapidjson parse 55952763 bytes in 239ms
nlohmann parse 55952763 bytes in 495ms
nlohmann parse 55952763 bytes in 491ms
nlohmann parse 55952763 bytes in 494ms
tao-json parse 55952763 bytes in 2178ms
tao-json parse 55952763 bytes in 2069ms
tao-json parse 55952763 bytes in 2056ms

Boost.JSON parse 488889121 bytes in 1820ms
Boost.JSON parse 488889121 bytes in 1831ms
Boost.JSON parse 488889121 bytes in 1835ms
rapidjson parse 488889121 bytes in 1860ms
rapidjson parse 488889121 bytes in 1886ms
rapidjson parse 488889121 bytes in 1828ms
nlohmann parse 488889121 bytes in 4195ms
nlohmann parse 488889121 bytes in 4241ms
nlohmann parse 488889121 bytes in 4320ms
tao-json parse 488889121 bytes in 22952ms
tao-json parse 488889121 bytes in 23265ms
tao-json parse 488889121 bytes in 23117ms

Here's a profile of an optimized build calling just tao-json for parsing:
<https://i.imgur.com/I7QLPkn.png>

It seems like there's this thing called PEGTL which has some large
number of functions showing up as taking up time in the profile? What
is PEGTL?

Thanks