Re: igc, macOS avoiding signals

[Pip Cet via "Emacs development discussions." <emacs-devel@gnu.org>]

"Helmut Eller" <eller.helmut@gmail.com> writes:

> On Mon, Dec 30 2024, Gerd Möllmann wrote:
>> Anyway, it definitely seems to be the case that MPS is _not_ running GCs
>> concurrently, unless it would do things that I find highly unlikely.
>>
>> I find that a bit, let's say, disappointing, TBH :-(.
>
> Richard Brooksby thinks[*] that MPS could be concurrent with software
> barriers.  Feel like going down that road? :-)

I saw that, but it's from 2008, so I'm not sure whether things changed
after that.

Note that for typical Emacs usage, I'd look into making the
stop-the-world phase of GC interruptible rather than nonexistent.  MPS
has a lot of code to deal with failed scans, so we could find one of
those code paths that fails non-catastrophically and fail it.

That we didn't make the old GC interruptible still seems like a mistake
to me, but for igc it means that we'll be able to pass that off as a new
feature.  Kind of like purespace, the old code we compare again always
had a hand tied behind its back.  (Helmut very impressively demonstrated
that for purespace, so this assumes he doesn't get around to
implementing interruptible mark-and-sweep GC before breakfast).

Pip