Re: [PATCH 7/7] dynamic calculation of event message size for ctnetlin

[Fabian Hugelshofer <hugelshofer2006@gmx.ch>]

Pablo Neira Ayuso wrote:
> Fabian Hugelshofer wrote:
>> Pablo Neira Ayuso wrote:
>>> [PATCH] dynamic calculation of event message size for ctnetlink
>>>
>>> This patch adds dynamic message size calculation for ctnetlink. This
>>> reduces CPU consumption since the overhead in the message trimming
>>> is removed.
>> Thanks for the patch.
>>
>> Just did some performance tests. On average it saves 5% CPU usage at
>> ~1600pps (UDP packets, 1000B payload, random source ports) on my router
>> (IXP4XX, 266Mhz).
>>
>> With the unclean patch the performance gain was slightly higher. I have
>> posted it was 10%, but as far as I remember it was actually a bit less
>> then that. The remaining difference can be explained by the length
>> calculation overhead and measuring inaccuracy.
> 
> How are you measuring CPU consumption? I would not trust "top" or
> something similar too much. I usually use cyclesoak, however I guess
> that you'll need a bit of hacking to get it working there.
> 
> I'll try to do some measurements in my platform soon anyway.

I am using top indeed. I run it in batch mode with a period of 10s and 
dump to a file. At the end I calculate the average idle usage over 5 
periods (ignoring the first one).