BIGpedia - BogoMips - Encyclopedia and Dictionary Online

BogoMips (from "bogus" and MIPS) are 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".

As a very approximate guide, the BogoMips can be pre-calculated by the following details:

SYSTEM                      RATIO                INDEX
Intel 8088                  clock * 0.004         0.02
Intel/AMD 386SX             clock * 0.14          0.8
Intel/AMD 386DX             clock * 0.18          1 (definition)
Motorola 68030              clock * 0.25          1.4
Cyrix/IBM 486               clock * 0.34          1.8
Intel Pentium               clock * 0.40          2.2
Intel 486                   clock * 0.50          2.8
AMD 5x86                    clock * 0.50          2.8
Mips R4000/R4400            clock * 0.50          2.8

Motorola 68040              clock * 0.67          3.7
PowerPC 603                 clock * 0.67          3.7
Intel StrongArm             clock * 0.66          3.7
Nexgen Nx586                clock * 0.75          4.2
PowerPC 601                 clock * 0.84          4.7

Alpha 21064/21064A          clock * 0.99          5.5
Alpha 21066/21066A          clock * 0.99          5.5
Alpha 21164/21164A          clock * 0.99          5.5
Intel Pentium Pro           clock * 0.99          5.5
Cyrix 5x86/6x86             clock * 1.00          5.6
Intel Pentium II/III        clock * 1.00          5.6
AMD K7/Athlon               clock * 1.00          5.6
Intel Celeron               clock * 1.00          5.6
Intel Itanium               clock * 1.00          5.6
Mips R4600                  clock * 1.00          5.6

Intel Itanium 2             clock * 1.49          8.3
Alpha 21264                 clock * 1.99         11.1
Centaur VIA                 clock * 1.99         11.1
AMD K5/K6/K6-2/K6-III       clock * 2.00         11.1
AMD Duron/Athlon XP         clock * 2.00         11.1
UltraSparc II               clock * 2.00         11.1
Pentium MMX                 clock * 2.00         11.1
Pentium 4                   clock * 2.00         11.1
Centaur C6-2                clock * 2.00         11.1
PowerPC 604/604e/750        clock * 2.00         11.1
Motorola 68060              clock * 2.01         11.2
Intel Xeon (hyperthreading) clock * 3.97         22.1

Hitachi SH-4                clock * 1
IBM S390                    not enough data (yet)
Intel ARM                   not enough data (yet)

The ratio is the typical ratio for that CPU with the then current Linux version. Since some caching aspects have been changed for some CPUs (notably the Intel ones) in the development of the kernel, other ratios may be applicable to those CPUs as well. Full and complete information and details about BogoMips, and hundreds of reference entries can be found in the BogoMips mini-Howto (see below).

BogoMips

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