MFC r342810:
powerd(8): allow to force a method of battery state query

This change allows to determine power source via sysctl or /dev/apm
when devd(8) is running (used by default).

Based on patch from PR; other changes on top of it:
- '-f' (force) -> '-s' (source) parameter renaming;
- allow 'apm' -> 'devd' transition when '-s devd' is set
(if APM is enabled);
- man page update.

PR: 125707
Submitted by: Konstantin Stepanov <milezv@yandex.ru>
Reviewed by: bcr, imp
Differential Revision: https://reviews.freebsd.org/D18742

MFC r280286: Add comment explaining existing powerd behavior on SMP systems.

MFC: r261773

In acline_init(), initialize ac_line to SRC_UNKNOWN. Previously
this could lead to the -n option effectively being ignored (in case
ac_line happened to be 0 aka SRC_AC), or other undefined behaviour.

PR: 169779
Submitted by: Alex Gonzalez <loox at e-shell.com>
Reviewed by: jhb

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Whitespace fixes: remove tabs on blank links, spaces following content,
tabs after spaces.

Reviewed by: gjb
MFC after: 1 week

Put the power modes in a list to make them easier to find.

Reviewed by: joel
MFC after: 1 week

Improve error reporting when no cpufreq(4) support is available.

Reviewed by: njl, acpi

Add missing static keyword.

All global variables and functions in powerd are marked static, except
this array of strings. Add the keyword, for consistency.

Add -m and -M options to control the minimum and maximum frequency.

PR: bin/145063
Submitted by: Boris Kochergin <spawk at acm.poly.edu>
Reviewed by: cperciva
Approved by: rrs (mentor)
MFC after: 2 weeks

Freq sysctls are quite heavy due to set of malloc()/free() calls. Avoid
reading current frequency on every period. Instead do it only after
changing and periodically from time to time if somebody else change it.

Also dynamically decrease sampling frequency up to 4 times on inactivity,

then -> than

MFC after: 1 day

Since APM is a legacy technology, that won't be adapted to other
platforms, move the test for i386 from the Makefile to powerd.c. The
powerpc specific checks are already done this way...

The last big commit: let usr.sbin/ use WARNS=6 by default.

ANSIfy almost all applications that use WARNS=6.

I was considering committing all these patches one by one, but as
discussed with brooks@, there is no need to do this. If we ever
need/want to merge these changes back, it is still possible to do this
per application.

Grammar and minor tweaks to powerd(8) man page.

PR: docs/133186
Approved by: ed (mentor)
MFC after: 2 weeks

Teach powerd how to query the PMU AC line state on PowerPC.

Fix a typo higter->higher.

Spotted by: ganbold

Restore original frequency on exit.

PR: bin/113813

Set of powerd enchancements:

1. Make it more SMP polite. Previous version uses average CPU load that
often leads to load underestimation. It make powerd with default
configuration unusable on systems with more then 2 CPUs. I propose to use
summary load instead of average one. IMO this is the best we can do without
specially tuned scheduler. Also as soon as measuring total load on SMP
systems is more useful then total idle, I have switched to it.

2. Make powerd's operation independent from number and size of frequency
levels. I have added internal frequency counter which translated into real
frequencies only on a last stage and only as good as gone. Some systems may
have only several power levels, while others - many of them, so adaptation
time with previous approach was completely different.

3. As part of previous I have changed adaptive mode to rise frequency on
demand up to 2 times and fall on 1/8 per time internal.

4. For desktop (AC-powered) systems I have added one more mode - "hiadaptive".
It rises frequency twice faster, drops it 4 times slower, prefers twice
lower CPU load and has additional delay before leaving the highest frequency
after the period of maximum load. This mode was specially made to improve
interactivity of the systems where operation capabilities are more
significant then power consumption, but keeping maximum frequency all the
time is not needed.

5. I have reduced default polling interval from 1/2 to 1/4 of second.
It is not so important for algorithm math now, but gives better system
interactivity.

Discussed on: mobile@

Add an abbreviation for adaptive mode, and document all the abreviations.

getopt(3) returns -1, not EOF.

Failing to set new frequency should not lead to powerd exiting.
Change err(3) to warn(3) as three other cases.

Approved by: njl, des

Back out revs 1.18 and 1.19; they were based on incorrect assumptions.

Requested by: nate

Look for cpu/ichss instead of cpu/p4tcc, which is i386/amd64-only.

Load cpufreq at startup if it isn't there already.

Don't use threads when there's no real reason to.

MFC after: 2 weeks

s/5.5/6.0/ in HISTORY section.

Discussed with: ru

-mdoc sweep.

Be more consistent with the rest of the manual page.

Create the devd thread after we have called daemon(). Otherwise, it would
be killed when the parent exits.

Submitted by: Rudolf Cejka <cejkar / fit.vutbr.cz>

Whitespace fix.

Set the signal handlers before creating the thread. This is so it inherits
the parent's signal mask. Once daemon() forked, signals would be ignored
in the child thread. While I'm here, check the return value of daemon().
This fixes termination in the daemon case (bug introduced in last commit).

Noticed by: Frederik Lindberg

Use a pipe for reading devd events as another method of getting the AC line
status. Add a thread that waits for events on the named pipe instead of
polling the line status via apm or the ACPI sysctl. Additionally, use
robust error handling in case devd goes away or we temporarily can't set
a frequency (i.e., passive cooling has preempted our setting).

Later, this should be improved so that if adaptive control is not being used,
we will block while waiting for AC line events, saving a little CPU.

Submitted by: Frederik Lindberg <fli+freebsd-current/shapeshifter.se>

Accept "maximum" and "minimum" modes as well as their abbreviations.

MFC after: 2 weeks

Test last minute changes, as gcc isn't too smart.

Reported by: Steve Kargl <sgk@troutmask.apl.washington.edu>

Add '-P' option which allows to specify pidfile.

Change the default adaptive algorithm for phk's one. Thanks to phk
and Kevin Oberman for this work.

Submitted by: Kevin Oberman
Reviewed by: njl
Approved by: njl

powerd(8) requires root permissions to run so notify the user if they
try to start it without this.

Submitted by: Philip S. Schulz
MFC after: 2 days

Ignore EPERM from sysctl(3). It is returned when passive cooling
is active.

Reviewed by: njl

Fixed markup.

Approved by: re

Drop the default running value to 60% from 80%. Testing shows that we
cycle too much, wasting power if we trigger a jump to full speed too
easily. CPU-bound tasks quickly push idle below this level.

Add support for recording the total energy used (in joules) when in
verbose mode. This is useful for profiling new adaptive algorithms
in performance (via time(1)) and total energy consumed for a given
workload.

man page -> manual page

Move the AC line checking code into its own function, reducing the
ifdef __i386__ stuff for APM. Tested as working correctly on i386 and
compile-tested on sparc64.

Unbreak !i386 platforms. Only i386 has APM, so don't try to fallback
on APM on other platforms.

Change the default levels for adaptive mode to 80% and 90%. On a system
with moderate IO going on, system usage can hover around 65-77% even
though it would benefit from higher performance. Typically, only truly
idle systems pass the 90% mark so only demote then.

Remove SRCS line since it isn't needed for single-source programs.
Pointed out by: ru

Import powerd(8), a utility for managing power consumption. Currently, it
just uses cpufreq(4) but in the future it should also do things like spin
down disks. This is based on the work by Colin Percival (called "estctrl").