Is Turbo Boost Working?

Question

I recently purchased a laptop with a sandy bridge CPU that is supposed to have turbo boost. Is turbo boost supported in 11.04? How can I tell if it's working?

I tried this but it seems to only detect nehelam CPUs.

Answer 1

11.04 runs the 2..6.38 kernel which is supposed to work well with Sandy Bridge CPUs.

You can open a terminal and run grep MHz /proc/cpuinfo. Then open a second terminal tab and run a loop like while :; do :; done. In the first terminal, run grep MHz /proc/cpuinfo again. You should see one of the cores has a higher frequency now:

$ grep MHz /proc/cpuinfo 
cpu MHz         : 1600.000
cpu MHz         : 1600.000
cpu MHz         : 1600.000
cpu MHz         : 1600.000
cpu MHz         : 1600.000
cpu MHz         : 3701.000
cpu MHz         : 1600.000
cpu MHz         : 1600.000

You can also try powertop and turbostat from the acpidump package (run sudo modprobe msr before sudo turbostat). The SVN version of i7z is supposed to work for Sandry Bridge (and it works for me with a desktop i7).

Answer 2

Use sudo turbostat for this. The output of cat /proc/cpuinfo does not always show the real current CPU frequency but instead the maximum non-turbo frequency even when Turbo Boost is enabled and active.

As stated in elmicha's answer, you'll need to load the msr module with sudo modprobe msr and then run turbostat with sudo turbostat.