How is bogomips computed?

[Yong Huang]

Even though bogomips as shown in /proc/cpuinfo is a rough estimation of CPU
capability, there must be some truth to it. Is it computed by doing a simple
busy loop to see how many iterations it can go through within some set time? I
can't imagine half of the CPUs on one of our boxes have only half the bogomips
of the others:

$ grep bogomips /proc/cpuinfo
bogomips        : 4018.62
bogomips        : 2009.31
bogomips        : 4018.62
bogomips        : 2009.31
bogomips        : 4018.62
bogomips        : 2009.31
bogomips        : 4018.62
bogomips        : 2009.31

Yong Huang