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On 01/21/2015 03:20 AM, Skamruk, Piotr wrote:
> On Wed, 2015-01-21 at 10:53 +0000, Skamruk, Piotr wrote:
>> On Tue, 2015-01-20 at 17:41 +0100, Tomasz Napierala wrote:
>>> [...]
>>> How this was measured? VM to VM? Compute to compute?
>> [...]
>> Probably in ~30 minutes we also will have results on plain centos with
>> mirantis kernel, and on fuel deployed centos with plain centos kernel
>> (2.6.32 in both cases, but with different patchset subnumber).
>
> OK, our test were done little badly. On plain centos iperf were runned
> directly on physical interfaces, but under fuel deployed nodes... We
> ware using br-storage interfaces, which in real are openvs based.
>
> So this is not a kernel problem, but this is a single stream over ovs
> issue.
>
> So we will investigate this further...
>

Not sure if iperf will emit it, but you might look at the bytes per 
receive on the receiving end.  Or  you can hang a tcpdump off the 
receiving interface (the br-storage I presume here) and see if you are 
getting the likes of GRO - if you are getting GRO you will see "large" 
TCP segments in the packet trace on the receiving side.  You can do the 
same with the physical interfaces for comparison.

2.5 to 3 Gbit/s "feels" rather like what one would get with 10 GbE in 
the days before GRO/LRO.

happy benchmarking,

rick jones
http://www.netperf.org/