Random numbers from CPU execution time jitter

I already saw HAVEGE used in cloud virtual machines, because /proc/sys/kernel/random/entropy_avail was too low. Virtual machines get no keyboard stroke nor hardware interrupts. The problem is not the quality the of entropy, but the quantity of entropy. Without HAVEGE, SSH quickly hangs at the connection after a few tries...

A better fix is to configure virtio-rng for the virtual machine.