calculating total CPU use in percentage

Question

So I am working in C and I am considering opening the proc/cpuinfo file and just extracting the data. (Honestly not even sure how to do that.) But I am not sure how to calculate it. Is it just CPU MHz divided by total CPU speed?

So in the above case, something like 900.160MHZ -> 0.9 GHz.

Total Cpu Usage = 0.9GHz/ 3.20GHz *100?

Also does anyone know a better way to do this?

No. Not at all. And this is not a programming question. Also, "total CPU speed" isn't a thing. — gspr, Feb 02 '22 at 14:52
Your questions aren't about doing this in C. They're about the concepts involved. (And 3.2 GHz is a clock frequency.) — gspr, Feb 02 '22 at 16:31

score 0 · Answer 1 · answered Feb 02 '22 at 15:04

You are looking at the wrong place for that. You are looking for cpu usage, and /proc/cpuinfo is not about that.

What you are looking for is this: https://www.idnt.net/en-GB/kb/941772

Additionally to files, you can get that from other linux commands suchas iostat, sar, etc.

There are also libraries to do that, such as Sigar.

sigar_t *sigar_cpu;
sigar_cpu_t old;
sigar_cpu_t current;
sigar_open(&sigar_cpu);
sigar_cpu_get(sigar_cpu, &old);
sigar_cpu_perc_t perc;
while(1)
{
    sigar_cpu_get(sigar_cpu, &current);
    sigar_cpu_perc_calculate(&old, &current, &perc);
std::cout &lt;&lt; &quot;CPU &quot; &lt;&lt; perc.combined * 100 &lt;&lt; &quot;%\n&quot;;
old = current;
Sleep(100);

}
sigar_close(sigar_cpu);
return 0;

And so many other ways! I am dropping some here!

Cheers!

calculating total CPU use in percentage

1 Answers1