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.It Fl p Ar hysteresis 77Percent of the upper limit to subtract as an hysteresis value to scale 78down to the min performance. 79The default is 10 80(meaning 10%). 81.It Fl r Ar poll_time 82Polling time in seconds. 83Default is 1.0. 84Setting this value lower will poll for load changes faster. 85For example, 86a workstation might want to use 0.2 or 0.4. 87.Nm can become unstable if you make this value too small. 88.It Fl t 89Turbo mode. 90Disables switching to turbo mode as maximum frequency completely. 91Switching to turbo mode as maximum frequency is enabled by default, 92if the CPU supports it. 93.It Fl u Ar trigger_up 94Per CPU load limit in percent to force maximum performance. 95The default is 25 96(meaning an instantanious load of 0.25 on a single cpu). 97The load is calculated over 3 polls. 98It is suggested that this value not be made lower than around 7. 99.It Fl B Ar minimum_battery_life 100If battery life is less than or equal to the specified value, 101the machine will start shutting down process. 102Default is 2 103(2% battery life left). 104.It Fl H Ar lowtemp:hightemp 105If the cpu temperature goes above lowtemp, powerd will begin ramping down 106the cpu frequency, reaching the lowest possible cpu frequency when the cpu 107temperature reaches hightemp. 108The default range is 75:85 (in degrees C), which tends to hold a laptop 109to ~80C under heavy load. 110Generally 111speaking, no machine cpu should be allowed to go above 80C even if the 112cpu can handle it, it means something is seriously wrong with your cooling 113system and you are stressing the cpu and mobo if you allow it. 114.Pp 115The default range starts at 75C. Most desktops with reasonable cooling 116will not exceed this value so it makes for a good default. Laptops can 117easily exceed 75C, sometimes reaching into the high 80's or even the 90's 118due to poor cooling and vendors tweaking their BIOS/fan-controls to the 119high side to do well in benchmarks. 120If you want your laptop to last, however, you really don't want it to get 121that hot. For powerd to be able to stabilize, we recommend that a minimum 122of a 10C range be used. So, for example, 70:80, or 75:85, and so forth. 123The user can change this range when starting powerd by adjusting 124.Va powerd_flags 125in 126.Pa /etc/rc.conf . 127.Pp 128This option can cause cpu fans to oscillate, and you may need to adjust the 129range if the oscillation is annoying to you. The basic reason for this is 130that small changes to the cpu frequency can have a huge effect on system 131power consumption, causing the BIOS-controlled fan to react, which in turn 132also changes the temperature and causes powerd to react. 133.It Fl L Ar battery_life_linger 134If battery life is less than or equal to the configured value, 135shutting down the machine will be delayed by the specified value. 136During the delay, 137alert message will be logged to the console, 138and audio alert will be alarmed. 139If AC line is plugged in during this delay, 140shutting down process will be cancelled. 141Default is 60 seconds. 142.It Fl P Ar battery_poll_interval 143Poll the battery life at the specified interval. 144If 0 is specified, 145battery life monitoring will be disabled. 146Default is 5 seconds. 147.It Fl Q 148Don't alarm audio alert, 149if the battery life is low. 150.It Fl T Ar sample_time 151Total sample interval in seconds. 152Default is 8.0. 153This effects how quickly powerd ratchets down the performance 154and cpus on an idle machine. 155Longer times will ratchet down more slowly. 156For example, 157a workstation might want to use a value of 30.0. 158.It Fl U 159Don't adjust userland scheduler's usable CPUs. 160.El 161.Sh EXIT STATUS 162The 163.Nm 164utility will exit with a non-zero code if required sysctls are not 165present. 166If the system is unable to report temperature, 167.Nm 168will still run, but will not be able to do any temperature-based frequency 169management. 170.Pp 171If a new instance of 172.Nm 173is run from the command line, it will automatically kill any previous 174instance running in the background. 175The system operator does not have to manually kill or signal 176.Nm 177when restarting it, simply invoke a new copy. 178.Sh EXAMPLES 179The defaults work well for servers but a workstation user might want 180to use something like the following in their 181.Pa /etc/rc.conf 182to ratchet up the machine more quickly in response to spike loads 183(such as when you are browsing). 184.Pp 185.Li powerd_enable="YES" 186.Pp 187.Li powerd_flags="-u 7 -r 0.2 -T 60" 188.Sh SEE ALSO 189.Xr acpi 4 , 190.Xr perfbias 4 191.Sh HISTORY 192The 193.Nm 194command first appeared in 195.Dx 2.7 . 196.Sh BUGS 197I'm shocked I tell you, 198shocked that there might be bugs in this program! 199