BogoMips (from "bogus" and MIPS) is a crude measurement of CPU speed made by the Linux kernel when it boots to calibrate an internal busy-loop.
[4] In 1993, Lars Wirzenius posted a Usenet message[5] explaining the reasons for its introduction in the Linux kernel on comp.os.linux: As a very approximate guide, the BogoMips can be pre-calculated by the following table.
[6][7] With the 2.2.14 Linux kernel, a caching setting of the CPU state was moved from behind to before the BogoMips calculation.
Note that a busy waiting technique is used, so the kernel is effectively blocked when executing ndelay/udelay functions.
[4] In 2012, ARM contributed a new udelay implementation allowing the system timer built into many ARMv7 CPUs to be used instead of a busy-wait loop.