bug#31138: Native json slower than json.el

[Eli Zaretskii]

> From: yyoncho <yyoncho@gmail.com>
> Date: Sun, 24 Mar 2019 22:57:58 +0200
> Cc: Sébastien Chapuis <sebastien@chapu.is>, 
>       31138@debbugs.gnu.org
> 
> From what I can see the Qbuffer_list_update_hook is called.

Is this with or without the patch I sent?

> 1. The hooks are not called initially, I am not sure what triggers them. This 
> makes the json parsing extremely
> slow(100 times)

The hooks are not called when decoding strings uses a fixed working
buffer that is created once and never killed.  Then something in your
setup causes this single working buffer to become in-use, and Emacs
then allocates an additional buffer, which is created and killed each
time we need to decode a string.  Both creating and killing of that
buffer runs the buffer-list-update-hook.

> 2. Even without the hooks, the JSON parsing is slower than the emacs -q 
> native parsing when I am running
> my setup. This will require additional investigation. 

Please, let's first finish fixing the factors we do understand already
and see what effect that produces.  Otherwise I don't see how we can
make steady progress in this matter.  That is why I sent an initial,
most probably incomplete patch.  Please apply it and see what it fixes
and what it doesn't fix.

I must rely on you in this matter, because I cannot reproduce the
slowdown on my system.

Thanks.