Re: [dpdk-dev] DPDK RSS support for ixgbevf PMD

["Ouyang, Changchun" <changchun.ouyang@intel.com>]

Hi ,

> -----Original Message-----
> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Vlad Zolotarov
> Sent: Tuesday, December 16, 2014 11:36 PM
> To: Thomas Monjalon
> Cc: dev@dpdk.org; Avi Kivity; Gleb Natapov
> Subject: Re: [dpdk-dev] DPDK RSS support for ixgbevf PMD
> 
> 
> On 12/15/14 22:33, Thomas Monjalon wrote:
> > 2014-12-15 21:11, Vladislav Zolotarov:
> >> Hi,
> >> I'm running an ixgbevf PMD on an AWS guests with extended networking
> >> (SR-IOV functions of 82599 Intel's NIC) and noticed that even in the
> >> current git tree there is no support for a multi-queue in this PMD:
> >> reta size returned by rte_eth_dev_info_get() call is 0, while
> >> max_rx_queues and max_tx_queues are both 4.
> >>
> >> Linux ixgbevf-2.15.3 driver on the other hand successfully
> >> initializes 2 RSS queues: for some reason it always limits the number of
> RSS queues by 2.
> >>
> >> ixgbevf_main.c: line 2539
> >> u16 rss = min_t(u16, num_online_cpus(), 2);
> >>
> >> The above is strange since if MRQE is set to 1010b there are 4 RSS
> >> queues available which seems to be the case in my AWS Guest.
> >>
> >> However, let's get back to DPDK. As I've mentioned above the SR-IOV
> >> function i have is RSS capable (to be 100% sure I've verified both
> >> queues are receiving packets in a multi-socket TCP test). And it's a
> >> shame I can't utilize it with a DPDK.
> > Yes, it is not yet supported.
> > But a patch was recently sent:
> > 	http://dpdk.org/ml/archives/dev/2014-December/010028.html
> 
> Applying this patchset seems to break the NIC fast path functionality of a
> AWS Guest NIC.
> I'm still debugging it - will update u as soon as I have more specific info.
> 
Pls make sure enabling and using 4 queues on guest if you enable vf rss on host and if each vf has 4 queues,
The packet could be received and put in any of 4 queues on guest depend on hash value of the packet.
You could let packet IP address increased continuously and make those packets distribute to different queues.

Thanks
Changchun