9600 was a standard baud rate decades ago, but 115200 is now more common
so choose defaults that are useful to the largest number of users.
Note that boot0sio does not support rates above 9600 so it remains
unchanged.
Reviewed by: bz, imp, manu
Relnotes: Yes
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D36295
Create a man page per loader. Loader(8) will have information common to
all of them, while loader_${INTERP}(8) will have information relevant to
that specific loader. Rewrite loader(8) to give an overview and point to
the appropriate man page. Rewrite each of the loader_${INTER}(8) man
pages to contain only the relevant information to that loader. Put all
the common commands, environment variables, etc in loader_simp(8) and
refernce that from the loader_lua or loader_4th man pages. The
loader_lua(8) could use more details about the Lua
integration. Additional organization may be benefitial.
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D31340
Booting FreeBSD on an EC2 c5.xlarge instance, the loader "twiddles"
810 times over the course of 510 ms, a rate of 1.59 kHz. Even accepting
that many systems are slower than this particular VM and will take
longer to boot (especially if using spinning-rust disks), this seems
like an unhelpfully large amount of twiddling when compared to the
~60 Hz frame rate of many displays; printing the twiddles also consumes
roughly 10% of the boot time on the aforementioned VM.
Setting the default globaldiv to 16 dramatically reduces the time spent
printing twiddles to the console while still twiddling at roughly 100
Hz; this should be ample even for systems which take longer to boot and
consequently twiddle slower.
Note that this can adjusted via the twiddle_divisor variable in
loader.conf, but that file is not processed until nearly halfway
through the loader's runtime.
Reviewed by: allanjude, jrtc27, kevans
MFC after: 1 week
Sponsored by: https://www.patreon.com/cperciva
Differential Revision: <https://reviews.freebsd.org/D32163>
loader_simp is a much simplified version of loader that will process a
linear sequence of commands from loader.rc. It has neither Forth nor Lua
built in and is much smaller. Document it. This is largely copied from
loader.8 since it implements those built-in commands. Future revisions
will fix this duplication.
Sponsored by: Netflix
