bug#64735: 29.0.92; find invocations are ~15x slower because of ignores

[Dmitry Gutov]

On 08/09/2023 09:35, Eli Zaretskii wrote:
> > > These questions can only be answered by dumping the values of the 2 GC
> > > thresholds and of consing_until_gc for each GC cycle.  It could be
> > > that we are consing more Lisp memory, or it could be that one of the
> > > implementations provides fewer opportunities for Emacs to call
> > > maybe_gc.  Or it could be some combination of the two.
> > Do you think the outputs of
> > https://elpa.gnu.org/packages/emacs-gc-stats.html  could help?
> I think you'd need to expose consing_until_gc to Lisp, and then you
> can collect the data from Lisp.

I can expose it to Lisp and print all three from post-gc-hook, but the 
result just looks like this:

gc-pct 0.1 gc-thr 800000 cugc 4611686018427387903

Perhaps I need to add a hook which runs at the beginning of GC? Or of 
maybe_gc even?

Alternatively, (memory-use-counts) seems to retain some counters which 
don't get erased during garbage collection.

> > All examples which use make-process call it with :connection-type 'pipe.
> >
> > The one that calls process-file (the "synchronous" impl) also probably
> > does, but I don't see that in the docstring.
> Yes, call-process uses pipes.  So finding the optimum boils down to
> running various scenarios.  It is also possible that the optimum will
> be different on different systems, btw.

Sure, but I'd like to improve the state of affairs in at least the main one.

And as for MS Windows, IIRC all find-based solution are currently slow 
equally, so we're unlikely to make things worse there anyway.