bug#65760: 29.1; eglot performance issue

[Eli Zaretskii]

Adding João.

> Cc: 65760@debbugs.gnu.org, glebsmirnov0708@gmail.com
> Date: Tue, 05 Sep 2023 19:22:15 +0300
> From: Eli Zaretskii <eliz@gnu.org>
> 
> > Cc: 65760@debbugs.gnu.org
> > From: Ivan Sokolov <ivan-p-sokolov@ya.ru>
> > Date: Tue, 05 Sep 2023 18:55:23 +0300
> > 
> > Глеб Смирнов <glebsmirnov0708@gmail.com> writes:
> > 
> > > The problem is that running eglot with rust-analyzer on my project
> > > causes major input lag. Profiling shows that the problem is in
> > > synchronous and slow function jsonrpc--log-event that is called on each
> > > server request or response. Disabling this function with (advice-add
> > > 'jsonrpc--log-event :override #'ignore) solves the problem.
> > 
> > To be more precise the problem is that jsonrpc--log-event is pretty
> > printing every reply from the server and they can be quite large and
> > nested.  I am attaching Gleb's profiler report, as a screenshot, but
> > this should be enough to give a better understanding of the problem.
> 
> Yes, the real CPU eater is pp-buffer.
> 
> But I also see that jsonrpc-request took a substantial amount of CPU
> time, and since jsonrpc-request runs from a timer, it is a good
> candidate for explaining a perceived lag.
> 
> Can you tell if this profile was in an Emacs build with built-in JSON
> support, or was Emacs using the Lisp implementation on json.el?
> 
> 
> 
>