Perf is a performance monitoring tool for Linux kernel available under "tools/perf". Install it on ubuntu :
$sudo apt-get install linux-tools-common linux-tools
More information is available at :
https://perf.wiki.kernel.org/
https://perf.wiki.kernel.org/articles/t/u/t/Tutorial.html
http://vger.kernel.org/~acme/perf/lk2010-perf-paper.pdf
