dummynet(4) kernel process CPU usage monitoring

[Eugene Grosbein]

21.11.2011 15:30, Luigi Rizzo пишет:
> On Mon, Nov 21, 2011 at 01:23:22PM +0700, Eugene Grosbein wrote:
>> Hi!
>>
>> I need to draw graph of dummynet's CPU usage.
>> "procstat -t 0" shows me TID (thread id) of dummynet kernel thread.
>> "ps -Hxo time,lwp" shows me total CPU time consumed by this thread.
>>
>> Now I see this time has 9 seconds increase during 60 seconds of real time.
>> This should be 9/60=15% CPU usage, but "top -SHP" shows me 0.00% meantime.
> 
> apart from the scaling on number of cores (e.g. if you have 8 cores
> the 15% becomes a bare 2%)

I have 4 cores (no hyperthreading) and it seems
that "top -SHP" does not scale anything in this mode.

> remember that percentages are computed
> with some kind of filtering (EWMA ?) so if the load of dummynet threads
> is bursty, the filter might eat most of it.

I do not understand what this filter is. Btw, dummynet load is steady here.
 
> not completely sure this explains a steady 0.00%, if that's is
> what you are seeing

Yes, I see 0.00% except of hours of most load where top shows about 10%
and ps shows about 30%.

Eugene Grosbein