Raspberry Pi BogoMIPS Is Dynamic!



Sponge Bob Sysadmin
"Raspberry Pi BogoMIPS is dynamic!" is something I imagine SpongeBob might say. Here he is, atop a Lego enclosure, and in the role of sysadmin for my Raspberry Pi Model B (circa 2011). 

The term BogoMIPS means "bogus millions of instructions per second," and provides a rough speed rating of a Linux system compared to an early model IBM PC.

You can determine your BogoMIPS with the following command:

$ grep Bogo /proc/cpuinfo

The early versions of Raspberry Pi calculated BogoMIPS once at boot time, and mine showed 2.00, which I took to mean it ran twice as fast the reference PC.  Later versions of Raspberry Pi showed the actual cpu frequency: 697.95 (700 MHz was the rated frequency).

With recent versions of Raspian -- Buster and the just released Bullseye -- I discovered, to my delight, that BogoMIPS was calculated dynamically based on the cpu load.  I tested using the Raspberry Pi 400, which has 4 cores.  At rest, the Pi produced these values:

BogoMIPS : 108.00
BogoMIPS : 108.00
BogoMIPS : 108.00
BogoMIPS : 108.00

Under stress, the Pi produced these values:

BogoMIPS : 324.00
BogoMIPS : 324.00
BogoMIPS : 324.00
BogoMIPS : 324.00

You can easily stress your system by running the "yes" command in another terminal:

$ yes "I'd like another raspberry pi please"

"yes" will echo your string to the console, or just a "y" if no string is specified, and it will continue to do so until you ctrl-c out of it.

A more fun way to stress your Pi is to have an ascii donut spinning in your terminal:

ASCII donut in a terminal



Donut is a clever C program which you can copy and compile yourself.  Coded by Andy Sloane, he also explains the math here

Donut was written in 2006, and I had to include <stdio.h> and <memory.h> for it to build successfully with a modern C compiler. 

To compile and link with the math library:

$ gcc -o donut donut.c -lm

Source code:

#include <stdio.h>
#include <memory.h>

             k;double sin()
         ,cos();main(){float A=
       0,B=0,i,j,z[1760];char b[
     1760];printf("\x1b[2J");for(;;
  ){memset(b,32,1760);memset(z,0,7040)
  ;for(j=0;6.28>j;j+=0.07)for(i=0;6.28
 >i;i+=0.02){float c=sin(i),d=cos(j),e=
 sin(A),f=sin(j),g=cos(A),h=d+2,D=1/(c*
 h*e+f*g+5),l=cos      (i),m=cos(B),n=s\
in(B),t=c*h*g-f*        e;int x=40+30*D*
(l*h*m-t*n),y=            12+15*D*(l*h*n
+t*m),o=x+80*y,          N=8*((f*e-c*d*g
 )*m-c*d*e-f*g-l        *d*n);if(22>y&&
 y>0&&x>0&&80>x&&D>z[o]){z[o]=D;;;b[o]=
 ".,-~:;=!*#$@"[N>0?N:0];}}/*#****!!-*/
  printf("\x1b[H");for(k=0;1761>k;k++)
   putchar(k%80?b[k]:10);A+=0.04;B+=
     0.02;}}/*****####*******!!=;:~
       ~::==!!!**********!!!==::-
         .,~~;;;========;;;:~-.
             ..,--------,*/


What could be more fun than a Raspberry Pi and a Donut?


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