Re: igc statistics display

[Eli Zaretskii <eliz@gnu.org>]

> From: Gerd Möllmann <gerd.moellmann@gmail.com>
> Cc: Emacs Devel <emacs-devel@gnu.org>
> Date: Fri, 10 Jan 2025 07:26:55 +0100
> 
> BTW, found this
> 
>   https://docs.python.org/3/howto/instrumentation.html
> 
> which basically says that Python can be built with Dtrace support that
> one can use to monitor Python processes.
> 
> I wonder if something like that wouldn't be interesting for Emacs also
> beyond monitoring GC activity.

We already have something similar for the display engine
(trace-redisplay), and it is indeed very useful for investigating
display problems.  So yes, I think that having a similar facility for
tracing GC in a build configured with --enable-checking=gc should be
useful.  However, it is possible that the means for activating the
trace, whether it should be a command or a variable or something else,
should be discussed, since GC is a more rare activity than redisplay,
so maybe the same model is not optimal here.

Whether this could be useful beyond GC is a separate issue.  One
complication is that different internal activities have different time
frames and different traits, so I'm not sure they can all be usefully
traced using the same commands/variables.  In addition, the sheer
flood of tracing outputs could well make this hard to use, even with
today's large screens.

So my gut feeling is that we should design the trace facilities
separately for each kind of internal activities.