turbostat on Linux: CPU Frequency, Temperature and Power Draw
To find out what’s really happening with your CPU — what frequency the cores run at, how much power it draws and how deeply it “sleeps” — Linux has a tool called turbostat.
In short: on Debian, turbostat is part of the linux-cpupower package. Install it and run turbostat as root — it reads data straight from the CPU’s model-specific registers (MSR).
How to install turbostat on Debian
apt install linux-cpupower
If turbostat says it can’t open /dev/cpu/0/msr, load the kernel module:
modprobe msr
How to run it
turbostat
It prints a table for every core and refreshes it every few seconds. Stop it with Ctrl+C.
To see only the essentials, pick the columns and the interval:
turbostat --quiet --interval 5 \ --show Busy%,Bzy_MHz,CoreTmp,PkgTmp,PkgWatt
What the columns mean
- Busy% — how busy the core was;
- Bzy_MHz — the core’s actual frequency while working (shows whether turbo boost kicked in);
- CoreTmp, PkgTmp — core and whole-CPU temperature;
- PkgWatt — how many watts the CPU draws;
- C1%, C6% etc. — how much time the core spent in sleep states (the deeper, the more energy saved).
turbostat is handy during a load test: you can see right away whether the CPU holds its frequency or hits its temperature limit and throttles. For why a CPU may run at a reduced frequency, see the post on cpu MHz 1600 on Debian.