I was wondering why the regression tests were substantially slower on my laptop running Ubuntu/Lucid compared to my desktop running Debian/stable. The laptop is newer and I was expecting it to be about 10% slower than the desktop, yet the laptop takes 17mins compared to 10mins for the desktop. It turns out to be AppArmor, installed by default in Ubuntu. Disabling AppArmor reduces the laptop time to 12mins, a considerable speed increase.
It might be possible to selectively disable AppArmor, but I simply disabled it globally: add "apparmor=0" to GRUB_CMDLINE_LINUX_DEFAULT in /etc/default/grub, run update-grub and reboot. -- Philip
