Re: Some experience with the igc branch

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

Gerd Möllmann <gerd.moellmann@gmail.com> writes:

> I'm using SIGPROF below to make it more concrete. Similar for other
> signals.
>
> The idea is to get the backtrace in the SIGPROF handler, without
> accessing Lisp data. That can be done, as I've tried to show.

I don't understand.  We need to access the specpdl, which I consider
Lisp data, and certainly the backtrace includes data which can only be
generated using MPS-managed memory.

> Then place that backtrace somewhere.

I still think it's better to copy the specpdl, since that allows us to
generate the "backtrace" (whatever we choose to use for that) in Lisp.
If we spend too much time allocating short-lived data which triggers too
many GCs, we want to know what to fix in the Lisp code.

Honestly, though, it doesn't matter much, does it?

> That's only one example architectures, of course. One can use something
> else, like queues that are handled by another thread, one doesn't need a
> scheduler thread, and so on, and so on. Pip's work queue is an
> example.

That's Helmut's code, not mine.

Pip