network performance

Stefan Lambrev stefan.lambrev at
Mon Feb 4 15:03:24 PST 2008

Stefan Lambrev wrote:
> 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:
> I forget this file :)
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