Re: [dpdk-dev] Fast Failover Test Results

[Stefan Binna <stefan.binna@salzburgresearch.at>]

Am 01.09.2015 um 18:03 schrieb Declan Doherty:
>
>
> On 01/09/15 14:31, Stefan Binna wrote:
>> Hi @all,
>>
>> I've conducted some fast failover tests on a SDN infrastructure, whereby
>> following three configurations were used for the device under test 
>> (DUT):
>>
>> - Intel 82574L with default driver e1000e
>> - Intel 82574L with DPDK
>> - Realtek RTL8111/8168/8411 PCI Express with default driver r8169
>>
>> There were two paths connected to the DUT, e.g. Path 1 and Path 2.
>> So by default Path 1 had been used. When Path 1 was disconnected, the
>> time it took to switch to Path 2 had been measured by counting the lost
>> packets.
>> Several tests have been conducted and the median calculated.
>>
>> Terminology:
>>
>> Median FF: Median fast failover time / ms
>> Median LP: Median lost packets / packet(s)
>>
>>                       Median FF   Median LP
>>
>> DPDK            1700            3363
>> Intel              350              690
>> Realtek         350              695
>>
>> Anyone an idea why DPDK is so "slow"?
>>
>> Best regards,
>>     Stefan.
>
> Hey Stefan,
>
> A couple of questions regarding your setup which will hopefully help 
> me figure out what the issue is.
>
> - Are you just running in active backup mode or are you using  one of 
> the other bonding modes.
> - What is down stream of the DUT, is it a switch or are you just 
> directly connected to another system?
>
> I'm not sure if the 82574L has LSC interrupt support in DPDK, I'll 
> check that out, but if it doesn't the PMD need will be polling the 
> link status which could be slowing down detection of the link going 
> down and the fail over to the over port.
>
> Declan
>
>

Hi Declan,

regarding your first question I think that I use the active backup mode, 
but I didn't define anything special.

What I did was starting OpenvSwitch with DPDK using following command(s):

# Start OVS with DPDK portion using 2GB of node 0 memory
./ovs/vswitchd/ovs-vswitchd --dpdk -c 0xf -n 4 --socket-mem 2048,0 -- unix:/usr/local/var/run/openvswitch/db.sock --pidfile --detach

Afterwards I added the interfaces which have been bound to the igb_uio 
driver as "dpdk interfaces":

./ovs/utilities/ovs-vsctl add-port br0 dpdk0 -- set Interface dpdk0 type=dpdk
sleep 0.5
./ovs/utilities/ovs-vsctl add-port br0 dpdk1 -- set Interface dpdk1 type=dpdk
sleep 0.5
./ovs/utilities/ovs-vsctl add-port br0 dpdk2 -- set Interface dpdk2 type=dpdk
sleep 0.5

The downstream of the DUT is connected to another switch.
Here is a network diagram: http://abload.de/img/ff_testbed_dpdk28sah.png
whereby al40-118 is the DUT, al40-115 the sender and al40-111 the receiver.

Thanks very much.

Stefan.