What are BogoMips

in Categories News 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

Anyone any more ideas or suggestion…?

Posted by: Vivek Gite

The author is the creator of nixCraft and a seasoned sysadmin and a trainer for the Linux operating system/Unix shell scripting. He has worked with global clients and in various industries, including IT, education, defense and space research, and the nonprofit sector. Follow him on Twitter, Facebook, Google+.

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