Until the past year I never truly appreciated how much faster make will build an executable when you are running on some heavy iron and use the -j option. As a p5p committer I have a shell account on dromedary, a server donated by booking.com++ and maintained by Dennis Kaarsemaker and friends (more ++). On that box I set TEST_JOBS=8, which enables me to configure, build and test perl so fast that I have never bothered to time it (probably less than 5 minutes).

Today, however, was the first time that I learned that running make -j${TEST_JOBS} can obscure the results of make.