Re: MPS: User GC customizations

[Eli Zaretskii <eliz@gnu.org>]

> Date: Thu, 04 Jul 2024 15:52:35 +0000
> From: Pip Cet <pipcet@protonmail.com>
> Cc: Gerd Möllmann <gerd.moellmann@gmail.com>, yantar92@posteo.net, emacs-devel@gnu.org, eller.helmut@gmail.com
> 
> On Thursday, July 4th, 2024 at 15:48, Eli Zaretskii <eliz@gnu.org> wrote:
> > > From: Gerd Möllmann gerd.moellmann@gmail.com
> > 
> > > Cc: yantar92@posteo.net, pipcet@protonmail.com, emacs-devel@gnu.org,
> > > eller.helmut@gmail.com
> > > Date: Thu, 04 Jul 2024 16:30:06 +0200
> > > 
> > > Eli Zaretskii eliz@gnu.org writes:
> > > 
> > > > > What this variable does is give MPS notice that the client is currently
> > > > > idle and it might be a good time to do some work.
> > > > 
> > > > Is that really what this variable does? My reading of the
> > > > documentation is that it tells MPS how soon to stop GC which it
> > > > started when Emacs was idle. IOW, it's not about triggering GC,
> > > > it's about ending it. And the reason, AFAIU, is to avoid making
> > > > Emacs responses slow because MPS started GC when it detected that
> > > > Emacs is idle.
> > > 
> > > I'm taking my view from this;:
> > 
> > 
> > I'm not sure what you are saying. You've cited exactly the same text
> > as I did, but didn't answer ny real question: does this variable work
> > as you said above ("give MPS notice that the client is currently
> > idle") or like I interpret it: tell MPS how much time it's okay to
> > spend in GC which it started when Emacs was idle?
> 
> I'm really confused. Can you explain what you think the difference is?

I just did, twice.  If that still doesn't explain it, then I guess my
explanatory talents betray me, and I don't know what else to say.

> The variable's value is a number. If the variable is zero, we don't tell MPS we're idle when we're idle. If it's nonzero, we tell it we're idle (when we are), and how much time it's okay to spend in GC.

The number can only tell one thing, not two.  AFAIU, it tells the
latter: "how much time it's okay to spend in GC" once GC started due
to idleness (and not some other reason).  Gerd said something
different: that this number "gives MPS notice" that Emacs is idle.
(How can a number "give notice" I don't understand even in principle.)