On Tue, Jan 04, 2022 at 02:31:44PM -0800, Walt Drummond wrote:

The only standard tools that support SIGINFO are sleep, dd and ping,
(and kill, for obvious reasons) so it's not like there's a vast hole
in the tooling or something, nor is there a large legacy software base
just waiting for SIGINFO to appear.   So while I very much enjoyed
figuring out how to make SIGINFO work ...

As far as I recall, GNU make on *BSD does support SIGINFO (Not a
standard tool, but obviously an established one).

The developers of strace have expressed interest in SIGINFO support
to print tracer status messages (unfortunately, not on a public list).
Computational software can use this instead of stderr progress spam, if
run in an interactive fashion on a terminal, as it frequently is. There
is a user base, it's just not very vocal on kernel lists. :)