1.\" (c) Copyright 2010 by Matthew Dillon and Dima Ruban. Permission to 2.\" use and distribute based on the DragonFly copyright. 3.\" 4.Dd August 16, 2015 5.Dt POWERD 8 6.Os 7.Sh NAME 8.Nm powerd 9.Nd simple CPU performance control and battery life monitor 10.Sh SYNOPSIS 11.Nm 12.Op Fl cdeftQU 13.Op Fl b Ar backlight_percentage 14.Op Fl h Ar highest_freq 15.Op Fl l Ar lowest_freq 16.Op Fl p Ar hysteresis 17.Op Fl r Ar poll_time 18.Op Fl u Ar trigger_up 19.Op Fl B Ar minimum_battery_life 20.Op Fl H Ar lowtemp:hightemp 21.Op Fl L Ar battery_life_linger 22.Op Fl P Ar battery_poll_interval 23.Op Fl T Ar sample_time 24.Sh DESCRIPTION 25The 26.Nm 27daemon monitors the CPU load and automatically adjusts the CPU 28performance up or down accordingly. 29.Pp 30The 31.Nm 32also monitors battery life. 33If the battery life is low 34(less than or equal to 2% by default), 35.Nm 36will send audio alert immediately, 37and shutdown the machine after lingering for a little while 38(60 seconds by default). 39.Pp 40The options are as follows: 41.Bl -tag -width ".Fl p Ar hysteresis" 42.It Fl b Ar backlight_percentage 43Set backlight to the specified percentage, 44if AC line is not plugged in. 45.It Fl c 46Enable mwait C-state hint adjustment, 47if it is available. 48.It Fl d 49Debug option. 50Causes 51.Nm 52to not go to the background and prints some debug output to 53.Va stdout . 54.It Fl e 55Enable Intel Performance and Energy Bias Hint adjustment, 56if it is available. 57.It Fl f 58Disable CPU power domain frequency adjustment. 59CPU power domain frequency adjustment does not reduce CPU power consumption 60much 61(if any) 62on some of the modern Intel CPUs, 63when the CPU is idle. 64.It Fl h Ar highest_freq 65If CPU power domain frequency adjustment is enabled, 66then frequency of CPU power domains will not be set to a value higher 67than the specified limit (unit: MHz). 68.It Fl l Ar lowest_freq 69If CPU power domain frequency adjustment is enabled, 70then frequency of CPU power domains will not be set to a value lower 71than the specified limit (unit: MHz). 72.Pp 73NOTE: This option is ignored if powerd is in temperature management. 74Temperature management will lower the frequency in excess of this value 75if necessary (but usually doesn't have to). 76.Pp 77NOTE: If you are using a serial port at 115200 baud, it is recommended 78you not allow the frequency to drop below 1500 Mhz or you might lose 79characters. 80.It Fl p Ar hysteresis 81Percent of the upper limit to subtract as an hysteresis value to scale 82down to the min performance. 83The default is 10 84(meaning 10%). 85.It Fl r Ar poll_time 86Polling time in seconds. 87Default is 1.0. 88Setting this value lower will poll for load changes faster. 89For example, 90a workstation might want to use 0.2 or 0.4. 91.Nm 92can become unstable if you make this value too small. 93.It Fl t 94Turbo mode. 95Disables switching to turbo mode as maximum frequency completely. 96Switching to turbo mode as maximum frequency is enabled by default, 97if the CPU supports it. 98.It Fl u Ar trigger_up 99Per CPU load limit in percent to force maximum performance. 100The default is 25 101(meaning an instantanious load of 0.25 on a single cpu). 102The load is calculated over 3 polls. 103It is suggested that this value not be made lower than around 7. 104.It Fl B Ar minimum_battery_life 105If battery life is less than or equal to the specified value, 106the machine will start shutting down process. 107Default is 2 108(2% battery life left). 109.It Fl H Ar lowtemp:hightemp 110If the cpu temperature goes above lowtemp, powerd will begin ramping down 111the cpu frequency, reaching the lowest possible cpu frequency when the cpu 112temperature reaches hightemp. 113The default range is 75:85 (in degrees C), which tends to hold a laptop 114to ~80C under heavy load. 115Generally 116speaking, no machine cpu should be allowed to go above 80C even if the 117cpu can handle it, it means something is seriously wrong with your cooling 118system and you are stressing the cpu and mobo if you allow it. 119.Pp 120The default range starts at 75C. Most desktops with reasonable cooling 121will not exceed this value so it makes for a good default. Laptops can 122easily exceed 75C, sometimes reaching into the high 80's or even the 90's 123due to poor cooling and vendors tweaking their BIOS/fan-controls to the 124high side to do well in benchmarks. 125If you want your laptop to last, however, you really don't want it to get 126that hot. For powerd to be able to stabilize, we recommend that a minimum 127of a 10C range be used. So, for example, 70:80, or 75:85, and so forth. 128The user can change this range when starting powerd by adjusting 129.Va powerd_flags 130in 131.Pa /etc/rc.conf . 132.Pp 133This option can cause cpu fans to oscillate, and you may need to adjust the 134range if the oscillation is annoying to you. The basic reason for this is 135that small changes to the cpu frequency can have a huge effect on system 136power consumption, causing the BIOS-controlled fan to react, which in turn 137also changes the temperature and causes powerd to react. 138.It Fl L Ar battery_life_linger 139If battery life is less than or equal to the configured value, 140shutting down the machine will be delayed by the specified value. 141During the delay, 142alert message will be logged to the console, 143and audio alert will be alarmed. 144If AC line is plugged in during this delay, 145shutting down process will be cancelled. 146Default is 60 seconds. 147.It Fl P Ar battery_poll_interval 148Poll the battery life at the specified interval. 149If 0 is specified, 150battery life monitoring will be disabled. 151Default is 5 seconds. 152.It Fl Q 153Don't alarm audio alert, 154if the battery life is low. 155.It Fl T Ar sample_time 156Total sample interval in seconds. 157Default is 8.0. 158This effects how quickly powerd ratchets down the performance 159and cpus on an idle machine. 160Longer times will ratchet down more slowly. 161For example, 162a workstation might want to use a value of 30.0. 163.It Fl U 164Don't adjust userland scheduler's usable CPUs. 165.El 166.Sh EXIT STATUS 167The 168.Nm 169utility will exit with a non-zero code if required sysctls are not 170present. 171If the system is unable to report temperature, 172.Nm 173will still run, but will not be able to do any temperature-based frequency 174management. 175.Pp 176If a new instance of 177.Nm 178is run from the command line, it will automatically kill any previous 179instance running in the background. 180The system operator does not have to manually kill or signal 181.Nm 182when restarting it, simply invoke a new copy. 183.Sh EXAMPLES 184The defaults work well for servers but a workstation user might want 185to use something like the following in their 186.Pa /etc/rc.conf 187to ratchet up the machine more quickly in response to spike loads 188(such as when you are browsing). 189.Pp 190.Li powerd_enable="YES" 191.Pp 192.Li powerd_flags="-u 7 -r 0.2 -T 60" 193.Sh SEE ALSO 194.Xr acpi 4 , 195.Xr perfbias 4 196.Sh HISTORY 197The 198.Nm 199command first appeared in 200.Dx 2.7 . 201.Sh BUGS 202I'm shocked I tell you, 203shocked that there might be bugs in this program! 204