[dpdk-dev] Packet drops during non-exhaustive flood with OVS and 1.8.0

Andrey Korolyov andrey at xdel.ru
Thu Feb 12 16:15:58 CET 2015


On Thu, Feb 12, 2015 at 6:05 PM, Traynor, Kevin <kevin.traynor at intel.com> wrote:
>> -----Original Message-----
>> From: Andrey Korolyov [mailto:andrey at xdel.ru]
>> Sent: Tuesday, February 3, 2015 5:21 PM
>> To: Traynor, Kevin
>> Cc: dev at dpdk.org; discuss at openvswitch.org
>> Subject: Re: Packet drops during non-exhaustive flood with OVS and 1.8.0
>>
>> > These patches are to enable DPDK 1.8 only. What 'bulk processing' are you referring to?
>> > By default there is a batch size of 192 in netdev-dpdk for rx from the NIC - the linked
>> > patch doesn't change this, just the DPDK version.
>>
>> Sorry, I referred the wrong part there: bulk transmission, which is
>> clearly not involved in my case. The idea was that the conditionally
>> enabling prefetch for rx queues (BULK_ALLOC) may help somehow, but
>> it`s probably will mask issue instead of solving it directly. By my
>> understanding, strict drop rule should have a zero impact on a main
>> ovs thread (and this is true) and work just fine with a line rate
>> (this is not).
>
> I've set a similar drop rule and I'm seeing the first packet drops occurring
> at 13.9 mpps for 64 byte pkts. I'm not sure if there is a config that can be
> changed or if it just the cost of the emc/lookups
>

Do you mind to compare this case with forward to the dummy port
(ifconfig dummy0; ovs-vsctl add-port br0 dummy0; ip link set dev
dummy0 up; flush rule table; create a single forward rule; start an
attack)? As I mentioned there are no signs of syscall congestion for a
drop or dpdk-dpdk forward case.


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