devd: Improve devmatch support

[imp]

Summary

We know that calling devmatch will be futile if there's no plug and play
information for it to match on. Avoid this generically when we see
"? at +on"
which happens only when the location and pnpinfo aren't provided. Don't
call "service devmatch quietstart" here.

We also ignore ACPI devices with a _HID of none. These also will never
load a new driver, so avoid calling "service devmatch quietstart" here too.

Use the more compatct "$*" instead of "'?'$_" when calling "service
devmatch quietstart" since it will evaluate to the same thing.

On my laptop, this eliminates 45% of the calls to devmatch. While it
would be even better to integrate devmatch into devd (so we only parse
linker.hints once), that will have to wait for another day as it's a bit
more complex to arrange that avoiding easy to avoid calls.

Sponsored by: Netflix

[jrtc27]

s/that/than/ in "more complex to arrange that avoiding easy to avoid calls."?

[imp]

In D42326#965928, @jrtc27 wrote:

s/that/than/ in "more complex to arrange that avoiding easy to avoid calls."?

Yes

[cperciva]

On my Framework laptop (where I was running recent tests and posting on twitter), this shaves off about 0.7 seconds of boot time and 333 processes. But that's under 20% of the time spent in devd so there's still more investigation to be done.

If you want to get this into 14.0 I won't say no, but gjb might deem it insufficiently critical for inclusion this late in the release cycle. I'll definitely poke at this more after the release and see if I can speed things up for 14.1.

[emaste]

sbin/devd/devmatch.conf

13

maybe remove this one too?

[emaste]

If you want to get this into 14.0 I won't say no, but gjb might deem it insufficiently critical for inclusion this late in the release cycle. I'll definitely poke at this more after the release and see if I can speed things up for 14.1.

It's fine for this to be an improvement in 15.0 or 14.1.