Re: division and cpu usage

[Jan Engelhardt]

On Aug 28 2007 00:07, Luka Napotnik wrote:
>>>> 2. I'm trying to get the percentage of CPU used for a certain
>>>> task_struct and figured the following formula:
>>>>
>>>> (task->utime + task->stime) / jiffies
>
>This formula just doesn't work. I have a task with 99% CPU (top) but the
>result of that formula is random (4, sometimes 8). What am I doing
>wrong? Please help.

You are calculating the CPU time the process has used since the start.
That is definitely not the same as the "%CPU" that top shows, more like
the "TIME+" top shows by default.

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