On 12/19/22 16:03, David Marchand wrote:
> The DPDK vhost-user library maintains more granular per queue stats
> which can replace what OVS was providing for vhost-user ports.
> 
> The benefits for OVS:
> - OVS can skip parsing packet sizes on the rx side,
> - vhost-user is aware of which packets are transmitted to the guest,
>   so per *transmitted* packet size stats can be reported,
> - more internal stats from vhost-user may be exposed, without OVS
>   needing to understand them,

Hi, David and Maxime.  Thanks for the patch!

The change looks good to me in general.  I would like to avoid some
of the code duplication it introduces, but I'm not sure how to actually
do that, so it's fine as is.

However, while testing the change I see a noticeable performance
degradation in a simple V-to-V scenario with testpmd and virtio-user
ports.  Performance dips by 1-3%.  It looks like the code added
to DPDK for some reason a bit heavier than code removed from OVS,
so they do not even out the packet rate with the current master.

If I'm commenting out enabling of the RTE_VHOST_USER_NET_STATS_ENABLE
flag, I can get performance back.  And it's even a bit higher, but
not high enough to compensate for stats accounting in vhost library
if stats are enabled.

Could you, please, check?  Maybe I'm missing something.

Best regards, Ilya Maximets.
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