network performance

[Stefan Lambrev]

Andrew Thompson wrote:
> On Mon, Feb 04, 2008 at 05:26:35PM +0200, Stefan Lambrev wrote:
>   
>> Greetings,
>>
>> In my desire to increase network throughput, and to be able to handle more 
>> then ~250-270kpps
>> I started experimenting with lagg and link aggregation control protocol 
>> (lacp).
>> To my surprise this doesn't increase the amount of packets my server can 
>> handle
>>
>> Using lagg doesn't improve situation at all, and also errors are not 
>> reported.
>> Also using lagg increased content switches:
>>
>> Top showed for CPU states +55%   system, which is quite high?
>>
>> I'll use hwpmc and lock_profiling to see where the kernel spends it's time.
>>     
>
> Thanks for investigating this. One thing to note is that ip flows from
> the same connection always go down the same interface, this is because
> Ethernet is not allowed to reorder frames. The hash uses
> src-mac, dst-mac, src-ip and dst-ip (see lagg_hashmbuf), make sure when
> performance testing that your traffic varies in these values. Adding
> tcp/udp ports to the hashing may help.
>   
The traffic, that I generate is with random/spoofed src part, so it is 
split between interfaces for sure :)

Here you can find results when under load from hwpmc and lock_profiling:
http://89.186.204.158/lock_profiling-lagg.txt
http://89.186.204.158/lagg-gprof.txt