[ovs-discuss] SR-IOV and storage over OVS

[Jesse Gross]

On Mon, Apr 8, 2013 at 1:14 AM, Kristoffer Egefelt <kristoffer at itoc.dk> wrote:
> Makes perfect sense - but with openvswitch 1.7.1 I'm seeing stuff like:
>
> 2013-04-06T20:03:55Z|6338190|timeval|WARN|82 ms poll interval (24 ms user,
> 52 ms system) is over 52 times the weighted mean interval 2 ms (2423146772
> samples)
> 2013-04-07T03:48:04Z|6378252|timeval|WARN|context switches: 0 voluntary, 3
> involuntary
> 2013-04-08T08:08:30Z|6589218|poll_loop|WARN|wakeup due to [POLLIN] on fd 18
> (unknown anon_inode:[eventpoll]) at ../lib/dpif-linux.c:1183 (93% CPU usage)
>
> CPU usage above 90% on 2.4Ghz E5645 with ~300MB/s and ~300K packets/s.
> (Noticeable SSH latency - sub-second though)
> CPU usage above 60% with ~120MB/s and 100K packets.
>
> I know storage traffic will be jumbo frames and might not be as difficult to
> handle as normal traffic in OpenVSwitch - but I'd like to minimize the
> latency for the storage as much as possible.
>
> Any hints on what to do here, something looks wrong or is this expected ?
> Anybody able to recommend running storage with / without openvswitch ?

This is likely due more to flow setups than raw throughput so storage
traffic is less likely to be affected.