SIMPLE SOLUTIONS

POWERSTAT - reference manual online

A tool to measure power consumption.

Chapter
16 August, 2015
POWERSTAT(8)                         System Manager's Manual                         POWERSTAT(8)

NAME powerstat - a tool to measure power consumption
SYNOPSIS powerstat [options] [delay [count]]
DESCRIPTION powerstat measures the power consumption of a computer that has a battery power source or supports the RAPL (Running Average Power Limit) interface. The output is like vmstat but also shows power consumption statistics. At the end of a run, powerstat will calculate the average, standard deviation and min/max of the gathered data. Note that running powerstat as root will provide extra information about process fork(2), exec(2) and exit(2) activity.
OPTIONS powerstat options are as follow: -a enable all statistics gathering options, equivalent to -c, -f, -t and -H. -b redo a sample measurement if a system is busy, the default for busy is considered less than 98% CPU idle. The CPU idle threshold can be altered using the -i option. -c gather CPU C-state activity and show the % time and count in each C-state at the end of the run. -d delay specify delay in seconds before starting, default is 180 seconds when running on battery or 0 seconds when using RAPL. This gives the machine time to settle down and for the battery readings to stabilize. -D enable extra power stats showing all the power domain power readings. This cur‐ rently only applies to the -R RAPL option. -f compute an average frequency from all on-line CPU cores. Unfortunately a CPU core is always active to gather any form of stats because powerstat has to be running to do so, so these statistics are skewed by this. It is best to use this option with a reasonably large delay (more than 5 seconds) between samples to reduce the over‐ head of powerstat. -g show GPU power readings. Currently just Intel i915 is supported and one needs to run powerstat with root privilege to access the kernel i915 /sys debug interface. -h show help. -H show histogram of power measurements. -i threshold specify the idle threshold (in % CPU idle) to force a re-sample measurement if the CPU is less idle than this level. This option implicitly enables the -b option. -n no headings. Column headings are printed when they scroll off the terminal; this option disables this and allows one to capture the output and parse the data with‐ out the need to filter out the headings. -p redo a sample measurement if any processes fork(), exec() or exit(). -r redo if system is not idle and any processes fork(), exec() or exit(), an alias for -p -b. -R read power statistics from the RAPL (Running Average Power Limit) domains. This is supported by recent Linux kernels and Sandybridge and later Intel processors. This only covers some of the hardware in the machine, such as the processor package, DRAM controller, CPU core (power plane 0), graphics uncore (power plane 1) and so forth, so the readings do not cover the entire machine. Because the RAPL readings are accurate and available immediately, the start delay (-d option) is defaulted to zero seconds. -s this dumps a log of the process fork(), exec() and exit() activity on completion. -S use standard averaging to calculate power consumption instead of using a 120 second rolling average of capacity samples. This is only useful if the battery reports just capacity values and is an alternative method of calculating the power consump‐ tion based on the start and current battery capacity. -t gather temperatures from all the available thermal zones on the device. If there are no thermal zones available then nothing will be displayed. -z forcibly ignore zero power rate readings from the battery. Use this to gather other statistics (for example when using -c, -f, -t options) if powerstat cannot measure power (not discharging or no RAPL interface).
EXAMPLES Measure power with the default of 10 samples with an interval of 10 seconds powerstat Measure power with 60 samples with an interval of 1 second powerstat 1 60 Measure power and redo sampling if we are not idle and we detect fork()/exec()/exit() activity sudo powerstat -r Measure power using the Intel RAPL interface: powerstat -R Measure power using the Intel RAPL interface and show extra RAPL domain power readings and power measurement histogram at end of the run powerstat -RDH Measure power and redo sampling if less that 95% idle powerstat -i 95 Wait to settle for 1 minute then measure power every 20 seconds and show any fork()/exec()/exit() activity at end of the measuring powerstat -d 60 -s 20 Measure temperature, CPU frequencies, C-states, power via RAPL domains, produce his‐ tograms, don't print repeated headings and measure every 0.5 seconds powerstat -tfcRHn 0.5
SEE ALSO vmstat(8), powertop(8), power-calibrate(8)
AUTHOR powerstat was written by Colin King <@canonical.com> This manual page was written by Colin King <@canonical.com>, for the Ubuntu project (but may be used by others).
16 August, 2015 POWERSTAT(8)
This manual Reference Other manuals
powerstat(8) referred by power-calibrate(8)
refer to _exit(2) | fork(2) | power-calibrate(8) | powertop(8) | vmstat(8)