Good morning,
I meet the author of this project during lastest Kernel Recipes conference. He did a little presentation of Corefreq.
If you want a like version eyescandy of "cpupower monitor" you can test it :)
Be aware that it's not in production compatible, and some little bugs can remain.
The main architecture is base on a kernel module which pool each core internal performance counter, communicating with a daemon which aggregates data.
At the end you have a little console client which connects to daemon and render data.
Have fun :)