ccache has changed my life. I happened upon it while browsing Freshmeat. What is it? ccache caches object file output from your compiler and keeps it around across makes. When compiling the same file again, instead of going through the preprocess/compile thing again, the object file is simply supplied as the output from the compiler, speeding future builds 5-6 times. A user mode linux kernel make now runs in 20 seconds, versus 10 minutes.