[ovs-dev] VXLAN source port hashing performance problems

[Kyle Mestery (kmestery)]

On Nov 15, 2012, at 3:13 PM, Kyle Mestery (kmestery) <kmestery at cisco.com> wrote:
> On Nov 15, 2012, at 1:03 PM, Kyle Mestery (kmestery) <kmestery at cisco.com> wrote:
>> Jesse:
>> 
>> I modified the source port hashing for the VXLAN patch I submitted a few days ago,
>> but I've noticed when using the upstream source port hashing routine, performance
>> drops off by 3.5 times when using iperf between two VMs. From what I can tell, it
>> has to be that all skbuffs coming into the VXLAN tunnel have not already had their
>> rxhash set, and this function is what's killing performance. Let me share the details:
>> 
> I think I figured this out. The upstream source port selection algorithm is exploding flows
> in the fast path. Here are iperf runs with both and subsequent "ovs-dpctl dump-flows"
> commands for comparison. The first one is with the upstream version, the second is
> with the one in my patch. Note that I just piped "ovs-dpctl dump-flows" into wc to
> summarize the flow count.
> 
> Upstream verison:
> [root at linux-br ~]# iperf -c 10.1.2.14 && ovs-dpctl dump-flows | wc


Figured this out, fixing it now, will repost the patch with only this change soon.

Thanks,
Kyle