What are BogoMips

Posted by Vivek Gite [Last updated: March 1, 2006]

Have you ever wondered what are BogoMips? Especially when booting Linux kernel you see message as follows:

Calibrating delay using timer specific routine.. 3437.74 BogoMIPS (lpj=6875498)

The "Bogo" in BogoMIPs stands for bogus. According to BogoMips mini-Howto:

MIPS is short for Millions of Instructions Per Second.
It is a measure for the computation speed of a program.
Like most such measures, it is more often abused than used properly (it is very difficult to justly compare MIPS for different kinds of computers).
BogoMips are Linus's invention. The kernel (or was it a device driver?) needs a timing loop (the time is too short and/or needs to be too exact for a non-busy-loop method of waiting), which must be calibrated to the processor speed of the machine. Hence, the kernel measures at boot time how fast a certain kind of busy loop runs on a computer. "Bogo" comes from "bogus", i.e, something which is a fake. Hence, the BogoMips value gives some indication of the processor speed, but it is way too unscientific to be called anything but BogoMips.

Ok so all I understood from above definition is that it is a tiny C loop which is use to calculate timing for a loop (such as for loop).

I have also noticed command bogomips which prints BogoMIPS:

$ bogomips

Calibrating delay loop... 2228.22 BogoMIPS

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