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BogoMips (from "bogus" and MIPS) is an unscientific measurement of CPU speed made by the Linux kernel when it boots, to calibrate an internal busy-loop. An oft-quoted definition of the term is "the number of million times per second a processor can do absolutely nothing".

BogoMips can be used to see whether it is in the proper range for the particular processor, its clock frequency, and the potentially present CPU cache. It is not usable for performance comparison between different CPUs.

Proper BogoMips ratings


As a very approximate guide, the BogoMips can be pre-calculated by the following table. The given rating is typical for that CPU with the then current Linux version. The index is the ratio of "BogoMips per clock speed" for any CPU to the same for an Intel 386DX CPU, for comparison purposes.

With the 2.2.14 linux kernel, a caching setting of the CPU state was moved from behind to before the BogoMips calculation. Although the BogoMips algorithm itself wasn't changed, from that kernel onward the BogoMips rating for then current Pentium CPUs came out double. The changed BogoMips outcome had no effect on real processor performance.

Full and complete information and details about BogoMips, and hundreds of reference entries can be found in the BogoMips mini-Howto (see below).
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