CPU Energy Meter
CPU Energy Meter is a Linux tool that allows to monitor power consumption of Intel CPUs at fine time granularities (few tens of milliseconds). Power monitoring is available for the following power domains:
- per package domain (CPU socket)
- per core domain (all the CPU cores on a package)
- per uncore domain (uncore components, e.g., integrated graphics on client CPUs)
- per memory node (memory local to a package, server CPUs only)
- per platform (all devices in the platform that receive power from integrated power delivery mechanism, e.g., processor cores, SOC, memory, add-on or peripheral devices)
To do this, the tool uses a feature of Intel CPUs that is called RAPL (Running Average Power Limit), which is documented in the Intel Software Developers Manual, Volume 3B Chapter 14.9. RAPL is available on CPUs from the generation Sandy Bridge and later. Because CPU Energy Meter uses the maximal possible measurement interval (depending on the hardware this is between a few minutes and an hour), it causes negligible overhead.
CPU Energy Meter is a fork of the Intel Power Gadget and developed at the Software Systems Lab of the Ludwig-Maximilians-Universität München (LMU Munich) under the BSD License.
The recommended way is to download the latest Debian package and install it.
Dependencies of CPU Energy Meter are libcap,
which is available on most Linux distributions in package
libcap (e.g., Fedora)
libcap2 (e.g, Debian and Ubuntu:
sudo apt install libcap2),
and a Linux kernel with the MSR and CPUID modules (available by default)
Alternatively, for running CPU Energy Meter from source (quick and dirty):
sudo apt install libcap-dev sudo modprobe msr sudo modprobe cpuid make sudo ./cpu-energy-meter
It is also possible (and recommended) to run CPU Energy Meter without root. To do so, the following needs to be done:
- Load kernel modules
- Add a group
- Add a Udev rule that grants access to
chmod 2711, and
setcap cap_sys_rawio=epon the binary (
make setupis a shortcut for this).
The provided Debian package does these steps automatically and lets all users execute CPU Energy Meter.
How to use it
cpu-energy-meter [-d] [-e sampling_delay_ms] [-r]
The tool will continue counting the cumulative energy use of all supported CPUs in the background and will report a key-value list of its measurements when it receives SIGINT (Ctrl+C):
+--------------------------------------+ | CPU-Energy-Meter Socket 0 | +--------------------------------------+ Duration 2.504502 sec Package 3.769287 Joule Core 0.317749 Joule Uncore 0.010132 Joule DRAM 0.727783 Joule PSYS 29.792603 Joule
To get intermediate measurements, send signal
USR1 to the process.
Optionally, the tool can be executed with parameter
to print the output as a raw (easily parsable) list:
cpu_count=1 duration_seconds=3.241504 cpu0_package_joules=4.971924 cpu0_core_joules=0.461182 cpu0_uncore_joules=0.053406 cpu0_dram_joules=0.953979 cpu0_psys_joules=38.904785
-d adds debug output.
By default, CPU Energy Meter computes the necessary measurement interval automatically,
this can be overridden with the parameter