dbd3197760
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@
141 lines
4.1 KiB
Groff
141 lines
4.1 KiB
Groff
.\" Copyright (c) 2005 Nate Lawson
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd November 6, 2005
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.Dt POWERD 8
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.Os
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.Sh NAME
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.Nm powerd
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.Nd "system power control utility"
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.Sh SYNOPSIS
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.Nm
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.Op Fl a Ar mode
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.Op Fl b Ar mode
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.Op Fl i Ar percent
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.Op Fl n Ar mode
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.Op Fl p Ar ival
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.Op Fl P Ar pidfile
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.Op Fl r Ar percent
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.Op Fl v
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.Sh DESCRIPTION
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The
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.Nm
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utility monitors the system state and sets various power control options
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accordingly.
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It offers three modes (maximum, minimum, and adaptive) that can be
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individually selected while on AC power or batteries.
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The modes maximum, minimum, adaptive and hiadaptive may be abbreviated
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max, min, adp, hadp.
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.Pp
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Maximum mode chooses the highest performance values.
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Minimum mode selects the lowest performance values to get the most power
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savings.
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Adaptive mode attempts to strike a balance by degrading performance when
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the system appears idle and increasing it when the system is busy.
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It offers a good balance between a small performance loss for greatly
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increased power savings.
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Hiadaptive mode is alike adaptive mode, but tuned for systems where
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performance and interactivity are more important then power consumption.
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It rises frequency faster, drops slower and keeps twice lower CPU load.
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The default mode is adaptive for battery power and hiadaptive for the rest.
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.Pp
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The
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.Nm
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utility recognizes the following runtime options:
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.Bl -tag -width ".Fl r Ar percent"
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.It Fl a Ar mode
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Selects the
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.Ar mode
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to use while on AC power.
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.It Fl b Ar mode
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Selects the
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.Ar mode
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to use while on battery power.
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.It Fl i Ar percent
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Specifies the CPU load percent level when adaptive
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mode should begin to degrade performance to save power.
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The default is 50% or lower.
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.It Fl n Ar mode
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Selects the
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.Ar mode
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to use normally when the AC line state is unknown.
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.It Fl p Ar ival
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Specifies a different polling interval (in milliseconds) for AC line state
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and system idle levels.
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The default is 250 ms.
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.It Fl P Ar pidfile
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Specifies an alternative file in which the process ID should be stored.
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The default is
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.Pa /var/run/powerd.pid .
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.It Fl r Ar percent
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Specifies the CPU load percent level where adaptive
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mode should consider the CPU running and increase performance.
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The default is 75% or higther.
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.It Fl v
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Verbose mode.
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Messages about power changes will be printed to stdout and
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.Nm
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will operate in the foreground.
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.El
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.Sh SEE ALSO
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.Xr acpi 4 ,
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.Xr apm 4 ,
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.Xr cpufreq 4
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.Sh HISTORY
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The
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.Nm
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utility first appeared in
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.Fx 6.0 .
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.Sh AUTHORS
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.An -nosplit
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.An Colin Percival
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first wrote
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.Nm estctrl ,
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the utility that
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.Nm
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is based on.
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.An Nate Lawson
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then updated it for
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.Xr cpufreq 4 ,
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added features, and wrote this manual page.
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.Sh BUGS
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The
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.Nm
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utility should also power down idle disks and other components besides the CPU.
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.Pp
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If
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.Nm
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is used with
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.Pa power_profile ,
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they may override each other.
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.Pp
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The
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.Nm
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utility
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should probably use the
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.Xr devctl 4
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interface instead of polling for AC line state.
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