Re: JSON encoding and decoding performance

[Eli Zaretskii]

> From: Clément Pit--Claudel <address@hidden>
> Date: Sat, 15 Apr 2017 01:35:45 -0400
> 
> I'm running into performance issues with JSON encoding and decoding.  I have 
> a language mode whose eldoc function makes a call to a language server 
> running as a subprocess, and small lags tend to be visible when moving 
> quickly around the buffer.  Profiling suggests that roughly 25 percent of the 
> time is spent encoding and decoding JSON strings.

Can you show the profiles?  IME, the devil is almost always in the
details.

> Would there be strong objections to supporting a C JSON library in addition 
> to the current ELisp implementation?  This was suggested at one point in 
> https://lists.gnu.org/archive/html/bug-gnu-emacs/2015-03/msg00770.html .  It 
> would be similar in spirit to supporting libxml-parse-region along 
> xml-parse-region, and it could provide nice speed boosts to json-heavy ELisp 
> programs.

Since we have modules now, something that wasn't available back then,
you could roll your own library, right?

Anyway, I think more details about the bottlenecks would be necessary
to make the decision on what would be the best course of action.

Thanks.