CPU Cycles

Install perf:

sudo apt-get install linux-tools-common linux-tools-3.11.0-15-generic

(The second package must match your kernel version. You can first install just linux-tools-common and call perf to let it tell you which package it needs.)

Record some 10 seconds of backtraces on all your CPUs:

sudo perf record -g -a sleep 10

Analyse your recording:

sudo perf report