CPU usage of particular process

[neha naik]

Does your machine have multiple CPUs?

Regards,
Neha

On Mon, May 20, 2013 at 4:05 AM, Rahul Bedarkar <rpal143 at gmail.com> wrote:

> Hi,
>
> I am trying to write small program to get CPU usage for a particular
> process. My logic is to read user, nice, system, idle values from
> /proc/stat. Then read user and system time from /proc/<pid>/stat. Then wait
> for some time and again read same values. After that I am doing following
> calculations
> CPU% = (no_of_processor * (process_cpu_usage2-process_cpu_usage1) * 100 )
> / (total_cpu_usage2-total_cpu_usage1)
>
> When I compare my output with top, it looks like correct, but sometimes it
> is more than 100. Is my logic correct here ? Please correct me if I am
> worng.
>
> Regards,
> Rahul
>
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